DEVICE FOR INSPECTING SUBSTRATE HAVING IRREGULAR ROUGH
SURFACE AND INSPECTION METHOD USING SAME
TECHNICAL FIELD
[0001] The present invention relates to an inspection apparatus for inspecting a
substrate having irregular concavities and convexities (unevennesses, or protrusions and
recesses) used to produce, for example, an organic electroluminescent element, and an
inspection method based on the use of the same.
BACKGROUND ART
[0002] An organic electroluminescent element (or referred to as "organic light emitting
diode" as well, hereinafter referred to as "organic EL element") is known as a selfluminescent
(self-light emitting) type display element. The organic EL element has
higher visibility as compared with the liquid crystal element, and any backlight is
unnecessary therefor. Therefore, it is possible to realize the light weight. In view of the
above, research and development are vigorously pe~ormed in relation to the organic EL
element as a next-generation display element.
[0003] In the organic EL element, the positive holes introduced from a hole injection
layer and the electrons introduced from an electron injection layer are carried to a light
emitting layer respectively, they are recombined on organic molecules in the light
emitting layer to excite the organic molecules, and thus the light is released thereby.
Therefore, in order to use the organic EL element as a display apparatus, it is necessary
that the light coming from the light emitting layer should be efficiently extracted or
taken out from the element surface. For this purpose, a technique is known as
described, for example, in Patent Document 1, in which a diffraction grating substrate is
provided on a light extraction surface of the organic EL element.
PRECEDING TECHNICAL DOCUMENTS
2
Patent Documents:
[0004]
Patent Document 1: JP2006-236748A;
Patent Document 2: W02011/007878Al.
SUMMARY OF THE INVENTION
Task to Be Solved by the Invention:
[0005] In the meantime, the present applicant has disclosed the following method in
Patent Document 2. That is, a solution, which is obtained by dissolving, in a solvent, a
block copolymer that fulfills a predetermined condition, is applied onto a base membe ~.
and drying is performed to form a micro phase separation structure of the block
copolymer, thereby obtaining a master block (mold) (metal substrate) in which a fme
(minute) and irregular concave-convex pattern is formed. According to this method, it
is possible to obtain the master block usable for the nano-imprint and the like by using a
self-organizing phenomenon of the block copolymer. A mixture of a silicone-based
polYI!ler and a curing agent is dropped onto the obtained master block and then cured to
obtain a transferred pattern. Then, a glass substrate coated with a curable resin is
pressed to (against) the transferred patt~m, and the curable resin is cured by irradiation
with an ultraviolet light. In this way, ~ diffraction grating in which the transferred
pattern is duplicated is manufactured. It has been confirmed that an organic EL element
obtained by stacking a transparent electrode, an organic layer, and a metal electrode on
the diffraction grating has sufficiently high light emission efficiency, sufficiently high
level of external extraction efficiency, while having sufficiently low wavelengthdependence
of light emission, sufficiently low directivity of light emission, and
sufficiently high power efficiency.
[0006] Even in the case of the organic EL element which uses the diffraction grating
produced in accordance with Patent Document 2 as described above, when the organic
EL element is used as a display device or an illumination device for a mobile phone or a
television screen, it is desirable that the light is radiated at a uniform luminance from the
entire display surface. Further, it is necessary to avoid the appearance of pattern defect
which causes the appearance of intensity fluctuation of light (strong light and weak
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light) at any minute portion of the display surface. For this reason, it is necessary to
confirm the fact that the irradiation from the organic EL element is uniform, i.e., the fact
that the luminance unevenness (uneven luminance) is within an allowable range and the
fact that the brightness or darkness does not arise at any minute portion, after the
completion of the organic EL element. However, if it is judged that the luminance
unevenness of the completed organic EL element or the brightness or darkness of the
minute portion is without the allowable range, then the organic EL element is regarded
as a defective product, and the step pf stacking the multiple layers on the diffraction
grating as described above becomes wasteful. In particular, the stacking of, for
example, the transparent electrode, the organic layer, and the metal electrode is the
laborious process in which the production cost is expensive. It is strongly demanded
that the defective product as described above is reduced to improve the yield and curtail
the wasteful use of the material and the production cost.
[0007] In order to evaluate the luminance unevenness, it is necessary that the inspection
should be performed simultaneously for a relatively large area. On the contrary, in order
to inspect the pattern defect which causes the light intensity fluctuation of the minute
portion, the inspection is performed in a relatively narrow field. Further, it is necessary
that the former inspection should not be affected by the latter inspection. Therefore, it is
necessary that the l~ance unevenness and the pattern defect should be inspected and
evaluated efficiently an4 independently. Furthermore, the substrate, which is the
inspection objective, is produced by performing the transfer process including, for
example, the nano-imprinting. Therefore, it is desirable the luminance unevenness and
the pattern defect are also inspected for that the metal mold as the transfer base and the
light transmissive mother substrate generated therefrom. For the way of use as
described above, it is desirable to adopt an inspection apparatus which can inspect not
only the light transmissive substrate but also the light non-transmissive substrate.
Moreover, the device, which includes, for example, a sensor for measuring the
uniformity of light and the luminance from the display surface having a large area (areal
size), is relatively expensive.
[0008] In view of the above, an object of the present invention is to provide an
inspection apparatus and an inspection method which make it possible to efficiently
inspect, at low cost, both of the luminance unevenness and the local pattern defect of a
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substrate having an irregular concave-convex surface. Another object of the present
invention is to provide an inspection apparatus and an inspection method which make it
possible to inspect both of the luminance unevenness and the pattern defect of any one
of a light transmissive substrate and a light non-transmissive substrate obtained when a
substrate having an irregular concave-convex surface is produced by performing a
transfer process.
Solution for the Task:
[0009] According to a first aspect of the present invention, there is provided a substrate
inspection apparatus for inspecting a substrate having an irregular concave-convex
surface for scattering lights, comprising:
a first irradiation system which irradiates the substrate with a fust detection
light;
a first detection system which detects any luminance unevenness from the entire
concave-convex surface of the substrate irradiated with the first detection light;
a second irradiation system which irradiates the substrate with a second
detection light having a wavelength different from that of the first detection light; and
a second detection system which detects any defect of the concave-convex
surface of the substrate irradiated with the second detection light.
[0010] In the substrate inspection apparatus of the present invention, the first detection
light may be a blue light, and the second detection light may be a white light.
[0011] In the substrate inspection apparatus of the present invention, the first irradiation
system may include a transmitting light illumination for illuminating a light
transmissive substrate and a non-transmitting light illumination for illuminating a light
non-transmissive substrate, and the second irradiation system may include a transmitting
light illumination for illuminating the light transmissive substrate and a non-transmitting
light illumination for illuminating the light non-transmissive substrate. Further, the
non-transmitting light illumination of the first irradiation system and the nontransmitting
light illumination of the second irradiation system may irradiate the
irregular concave-convex surface of the substrate, and the transmitting light illumination
of the first irradiation system and the transmitting light illumination of the second
irradiation system may irradiate the irregular concave-convex surface of the substrate
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from a surface disposed on a side opposite to the irregular concave-convex surface of
the substrate.
[0012] In the substrate inspection apparatus of the present invention, the first detection
system may include a camera which detects the light coming from the light transmissive
substrate illuminated with the transmitting light illumination of the first irradiation
system and the light coming from the light non-transmissive substrate illuminated with
the non-transmitting light illumination of the first irradiation system. Further, the
second detection system may include a camera which detects the light coming from the
light transmissive substrate illuminated with the transmitting light illumination of the
second irradiation system and the light coming from the light non-transmissive substrate
illuminated with the non-transmitting light illumination of the second irradiation system.
A resolution of the camera of the second detection system may be higher than a
resolution of the camera of the first detection system.
[0013] In the substrate inspection apparatus of the present invention, the camera of the
second detection system may include a plurality of cameras which detect divided areas
of the substrate respectively.
[0014] In the substrate inspection apparatus of the present invention, the first irradiation
system and the second irradiation system may be line-shaped illuminations, and the
apparatus may further comprise a substrate transport system which transports the
substrate in a direction perpendicular to a direction in which the line-shaped
illuminations extend.
[0015] The substrate inspection apparatus of the present invention may further comprise
a control system which controls the substrate transport system, the first irradiation
system, the second irradiation system, the first detection system, and the second
detection system, wherein the control system can detect the defect of the concaveconvex
surface when the substrate is moved by the substrate transport system in one
direction with respect to the first irradiation system, the second irradiation system, the
first detection system, and the second detection system, and the control system can
detect the luminance unevenness when the substrate is moved in a direction opposite to
the one direction with respect to the first irradiation system, the second irradiation
system, the first detection system, and the second detection system. Further, the control
system may judge whether or not the defect of the concave-convex surface and the
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luminance unevenness are within predetermined allowable ranges.
[0016] According to a second aspect of the present invention, there is provided an
inspection method for inspecting a light non-transmissive substrate having an irregular
concave-convex surface for scattering lights and a light transmissive substrate having an
irregular concave-convex surface for scattering lights, the inspection method
comprising:
transporting the substrate with respect to a first detection system which detects
any luminance unevenness from the entire concave-convex surface of the substrate and a
second irradiation system which detects any defect of the concave-convex surface of the
substrate;
irradiating the concave-convex surface of the substrate with a first detection light
to detect the light coming from the concave-convex surface by the first detection
system, and irradiating the concave-convex surface of the substrate with a second
detection light having a wavelength different from that of the first detection light to
detect the light coming from the concave-convex surface by the second detection
system, when the light non-transmissive substrate is transported; and
irradiating the irregular concave-convex surface of the substrate with the first
detection light from a surface of the light transmissive substrate disposed on a side
opposite to the concave-convex surface to detect the light coming from the concaveconvex
surface by the first detection system, and irradiating the irregular concaveconvex
surface of the substrate with the second detection light from the surface of the
light transmissive substrate disposed on the opposite side to detect the light coming
from the concave-convex surface by the second detection system, when the light
transmissive substrate is transported.
[0017] In the substrate inspection method of the present invention, the first detection
light may be a blue light, and the second detection light may be a white light.
[0018] In the substrate inspection method of the present invention, each of the first
irradiation system and the second irradiation system may be a line-shaped illumination
extending in a predetermined direction, and the substrate may be transported in a
direction perpendicular to the direction in which the line-shaped illumination extends.
[0019] In the substrate inspection method of the present invention, the defect of the
concave-convex surface of the substrate may be detected when the substrate is moved in
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one direction with respect to the first detection system and the second detection system,
and the luminance unevenness may be detected when the substrate is moved in a
direction opposite to the one direction with respect to the first detection system and the
second detection system.
[0020] The substrate inspection method of the present invention may further comprise
judging whether or not the defect of the concave-convex surface and the luminance
unevenness are within predetermined allowable ranges.
[0021] According to a third aspect of the present invention, there is provided a substrate
production method for producing a substrate having an irregular concave-convex
surface for scattering lights, comprising:
preparing the substrate having the irregular concave-convex surface; and
inspecting the substrate having the irregular concave-convex surface by using the
substrate inspection method as defmed in the first aspect of the present invention.
[0022] In the substrate production method of the present invention, the preparation of
the substrate having the irregular concave-convex surface may comprise preparing a
light non-transmissive substrate having an irregular concave-convex pattern, and
transferring the irregular concave-convex pattern of the light non-transmissive substrate.
[0023] In the substrate production method of the present invention, the preparation of
the substrate having the irregular concave-convex surface may comprise utilizing phase
separation of a block copolymer.
[0024] In the substrate production method of the present invention, the irregular
concave-convex surface may be formed of a metal, resin, or sol-gel material.
[0025] According to a fourth aspect of the present invention, there is provided a method
for producing an organic EL element, comprising preparing a diffraction grating
substrate having a concave-convex surface by using the substrate production method as
defined in the third aspect of the present invention, and successively stacking a
transparent electrode, an organic layer, and a metal electrode on the concave-convex
surface of the diffraction grating substrate to produce the organic EL element.
[0026] In the method for producing the organic EL element of the present invention, the
organic EL element may be produced by successively stacking the transparent electrode,
the organic layer, and the metal electrode on the concave-convex surface of the
diffraction grating substrate having the luminance unevenness within a predetermined
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allowable range and the defect within a predetermined allowable range only when it is
judged that the luminance unevenness and the defect of the prepared diffraction grating
substrate are within the predetermined allowable ranges.
EFFECT OF THE INVENTION
[0027] According to the substrate inspection apparatus and the substrate inspection
method of the present invention, the substrate having the irregular concave-convex
surface to be used for the element such as the organic EL element or the like can be
efficiently produced, while effectively inspecting the luminance unevenness and the
pattern defect of the substrate as described above. According to the method for
producing the organic EL element of the present invention, the organic EL element can
be produced at a high throughput by correlating the characteristic of the luminance
unevenness in relation to the organic EL element and the substrate having the irregular
concave-convex surface to be used therefor. In particular, the occurrence of the
luminance unevenness and the pattern defect of the finished product can be predicted
and the finished product can be evaluated at the stage of production of the substrate.
Therefore, the organic EL element having the uniform illuminance can be produced
more reliably by using the substrate which is judged to be acceptable in the judgment or
examination of the luminance unevenness and the pattern defect. Further, even when
the uniformity of the illuminance of the organic EL element is defective (luminance
unevenness) or even when the local light emission or the light reduction (extinction)
arises, then it is possible to know whether any defective product is appeared either at the
stage of formation of the substrate or at the stage of formation of the element itself.
Therefore, it is possible to quickly respond to such a situation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028]
Fig. 1 shows a flow chart illustrating a substrate inspection method of the
present invention.
Fig. 2 schematically shows a substrate inspection apparatus of the present
invention, wherein Fig. 2A shows a schematic side view, and Fig. 2B shows a schematic
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sectional view as viewed in a direction of m-m shown in Fig. 2A.
Fig. 3A conceptually shows a situation provided when a light transmissive
substrate is inspected by using a transmitting illuminatiqn for macro (for macro
inspection), and Fig. 3B conceptually shows a situation provided when a light nontransmissive
substrate is inspected by using a non-transmitting illumination for macro
(for micro inspection).
Fig. 4 shows an arrangement of a substrate as an inspection objective, a macro
camera, and micro cameras as viewed from a position over or above the inspection
apparatus.
Fig. 5 shows inspection images obtained from a substrate having a concaveconvex
pattern formed by using a sol-gel material on a glass substrate, wherein Fig. 5A
shows a micro inspection image, and Fig. 5B shows a macro inspection image.
Figs. 6A to 6D conceptually show the process for manufacturing the substrate by
the BCP method, conceptually illustrating the process to obtain a mountain-like
structure by performing a first heating step, an etcb..iD;g step, and a second heating step.
Fig. 7 conceptually shows the process to obtain wave-like structures by the BCP
method while performing a solvent annealing step, wherein Fig. 7 A shows a wave-like
structure in which the cylindrical arrangement includes a single layer, and Fig. 7B shows
a wave-like structure in which the cylindrical structure includes a plurality of layers.
Figs. 8A to 8D conceptually show the process for manufacturing a metal
substrate having a concave-convex structure by means of electroforming.
Figs. 9A to 9E conceptually show the process for manufacturing a diffraction
grating from a metal substrate having a concave-convex structure.
Figs. lOA to lOD conceptually show the process for manufacturing a concaveconvex
structure by means of the BKL method.
Fig. 11 shows a cross-sectional structure of an organic EL element.
Fig. 12 shows images as results of the macro inspection for a sol-gel material
substrate manufactured in Example 4, wherein Fig. 12A shows a macro inspection
image based on the use of an illumination having a light emission central wavelength of
460 nm, and Fig. 12B shows a macro inspection image based on the use of a white
illumination.
Figs. 13A to 13C conceptually show the procedure of the micro inspection
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process to perform the micro inspection at a high resolution in a modified embodiment
of the present invention.
MODE FOR CARRYING OUT THE INVENTION
[0029] An explanation will be made in detail below with reference to the drawings
about preferred embodiments of the substrate inspection apparatus according to the
present invention and the inspection method based on the use of the same. The
inspection apparatus and the inspection method of the present invention detect the
luminance unevenness and the defect of the concave-convex pattern of the substrate
having the irregular concave-convex surface.

[0030] The outline of the inspection method of the present invention will be explained
in accordance with a flow chart shown in Fig. 1. At first, a substrate having an irregular
concave-convex surface is manufactured or prepared (Sl). In this context, the term
"substrate having the irregular concave-convex surface" means the substrate in which
the concave-convex pattern formed on the substrate has no regularity, especially the
substrate in which the pitches of concavities and convexities are not uniform and no
directivity is provided in relation to the directions of the concavities and co~vexities.
The light, which is scattered and/or diffracted from the substrate as described above, is
not the light having either single wavelength or narrow band wavelengths, but the light
has a relatively wide wavelength band. The scattered light and/or the diffracted light
has no directivity, and the light is directed in all directions. However, the "substrate
having the irregular concave-convex surface" described above includes such a pseudoperiodic
structure that a Fourier transform image, which is obtained by applying the
two-dimensional high speed Fourier transform process to a concavity-convexity analysis
image obtained by analyzing the shapes of the surface concavities and convexities,
exhibits a circular or annular motif or marking (pattern), i.e., a distribution of the pitches
of concavities and convexities is provided although no directivity is provided for the
directions of the concavities and convexities. Therefore, the substrate, which has the
pseudo-periodic structure as described above, is preferred for the diffraction substrate to
be used, for example, for the surface light emission element such as the organic EL
11
element, provided that the distribution of the pitches of concavities and convexities
causes the diffraction of the visible ray. On the other hand, any substrate, which is
formed by arranging all of recording tracks (grooves) in an identical direction at an
identical pitch as exemplified by the optical recording ~edium and the magnetic
recording medium, does not fall under the "substrate having the irregular concaveconvex
surface" as referred to in this patent application. Details of the steps of
manufacturing the substrate having the irregular concave-convex surface will be
described later on.
[0031] Subsequently, the substrate havirig the irregular concave-convex surface is
inspected for the luminance unevenness of the substrate surface and the minute defect
(for example, pattern defect, foreign matter, scratch) in accordance with the inspection
step as described later on (S2). Further, the judgment is performed in accordance with
the judging step as described later on about whether or not the substrate has the uniform
luminance distribution and whether or not the minute defect is within the allowable
range, on the basis of the inspection result (S3). If the substrate has the uniform
luminance distribution and the detected minute defect is within the allowable range,
then the substrate is regarded as a finished product, and the substrate is used for the
process to be performed thereafter including, for example, the production of the organic
EL (S4). If it is judged that the substrate does not have the ~iform luminance
distribution or the minute defect is without the allowable r~ge, then the aftertreatment
is applied in accordance with the aftertreatment step as described later on (S5).

[0032] The substrate inspection apparatus according to the present invention will be
explained with reference to Figs. 2 to 4. An inspection apparatus 102 shown in Fig. 2A
mainly comprises, a transport system 108 which transports the substrate P from the
upstream side to the downstream side in the transport direction (arrow Y in the
drawing), a macro inspection unit 104, a micro inspection unit 106 which is provided on
the downstream side as compared with the macro inspection unit 104, and a control unit
111 therefor. In this specification, the transport direction of the inspection apparatus
102 is designated as "Y direction", the direction parallel to the substrate surface and
perpendicular to the transport direction is designated as "X direction", and the height
direction perpendicular to the substrate surface is designated as "Z direction". The
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transport system 108 is a conveyer in which a plurality 'of rollers 108 are arranged in the
transport direction. Some of the rollers 108a are driving rollers connected to a rotary
driving source (not shown), and the substrate P is moved from the upstream side to the
downstream side in the transport direction on the rollers 108a. A macro inspection
position MA and a micro inspection position MI exist approximately at the center in the
transport direction of the transport system 108. The method for transporting the
substrate is not limited to the transport based on the rollers. It is also allowable to
perform, for example, the transport based on a linear motor.
[0033] The macro inspection unit 104 is the unit for inspecting the luminance
unevenness of the entire surface of the substrate P transported by the transport system
108. The macro inspection unit 104 mainly comprises a transmitting light illumination
for macro 114 and a reflecting light (non-transmitting light) illumination for macro 116
which serve as an illumination system for macro (first irradiation system), and a macro
camera 112 which serves as a macro detection system (first detection system). The
detection objective of the macro detection system is the area (region) having an areal
size of not less than 0.1 mm2
•
[0034] The transmitting light illumination for macro 114 is the illumination which is
used to inspect the light transmissive substrate, and the transmitting light illumination
for macro 114 is provided under or below th~ transport system 108. In this
embodiment, a blue LED line-shaped illumip.ation, in which a plurality of blue LEDs for
emitting the light (first detection light) having a wavelength of 400 run to 500 nm are
embedded in a frame in an array form in the X direction, is used herein as the
transmitting light illumination for macro 114. The use of the blue LED line-shaped
illumination is advantageous in that i) the observation range can be uniformly
illuminated, ii) the unevenness appears clearly, and iii) any influence is hardly exerted
by any foreign matter. In view of the advantages as described above as well, it is
preferable that the transmitting light illumination for macro 114 is the blue LED lineshaped
illumination even when the substrate material is any one of film, glass, and
metal. The transmitting light illumination for macro 114 is attached rotatably about the
center of a rotary shaft 114a on a support base 114b so that the angle of incidence of the
illumination light can be regulated with respect to the substrate P (or a part thereof)
existing at the inspection position MA. As shown in Fig. 3A, the transmitting light
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illumination for macro 114 irradiates, with the light, the back surface of the substrate P
existing at the inspection position MA, i.e., the surface on which the concave-convex
structure is not formed. The light, which comes into the inside of the substrate P, is
scattered and diffracted by the concave-convex pattern on the surface of the substrate P.
[0035] The scattered and diffracted light, which comes from the concave-convex
structure, is received by the macro camera 112 which is installed over or above the
transport system 108 on the upstream side in the transport direction as compared with
the light irradiation unit. It is allowable that the macro camera 112 is an arbitrary image
pickup element provided that the element can receive the scattered light and the
diffracted light at the inspection position MA. A line sensor camera, which
continuously photographs or picks up the one-dimensional image when the substrate P
passes over the inspection position MA, is preferably used. When the line sensor
camera is used, the scattered and diffracted lights, which come from the substrate P, can
be always picked up at an identical angle. Note that the number of pixels of the image
pickup element is preferably at least not less than 30. For example, it is possible to use
a CCD camera of 80 ~pixel. In general, the macro camera 112 is arranged at the
position at which the primary diffracted light coming from the concave-convex pattern
existing at the inspection position MA can be received. The macro camera 112 is
attached to a movement stage .112a by the aid of an arm 112b having a rotary shaft. The
movement stage 112a is slidably movable on a stage base 112c. The macro camera 112
can be moved in the X direction and the optical axis direction of the macro camera 112.
Further, it is possible to change the angle of the optical axis of the macro camera 112
(receiving angle) by means of the rotary shaft of the arm 112b. Note that if a plurality of
macro cameras 112 are provided, then not only the influence, which is exerted, for
example, by the sensitivity error and the focal point adjustment among the cameras,
appears, but it also becomes necessary to combine the data of the respective cameras
with each other. In this case, the data processing becomes complicated. Therefore, it is
desirable to perform the inspection by using one macro camera 112.
[0036] The non-transmitting light illumination for macro 116 is the illumination which
is used to inspect the non-transmissive substrate. The non-transmitting light
illumination for macro 116 is provided on a support base 130 disposed over or above the
inspection position MA over or above the transport system 108. In this embodiment, a
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line-shaped illumination, in which LEDs for emitting the light having a wavelength of
400 run to 500 run are embedded in an array form in the X direction, is used as the nontransmitting
light illumination for macro 116. The non-transmitting light illumination
for macro 116 is provided slidably on a guide 116a so that the position and the angle of
light irradiation can be regulated. As shown in Fig. 3B, the non-transmitting light
illumination for macro 116 irradiates, with the light, the surface of the substrate P
existing at the macro detection position MA, i.e., the surface on which the concaveconvex
pattern is formed, and the reflected light coming from the surface of the
-
substrate P is scattered and diffracted by the concave-convex structure of the surface of
the substrate P. The scattered light and the diffracted light coming from the concaveconvex
structure are received by the macro camera 112. As described above, even when
the transported substrate is either light transmissive or non-transmissive, the macro
inspection unit 104 can inspect any substrate by properly using the illumination systems.
That is, the macro inspection unit 104 makes it possible to perform the both types of
macro inspection of the light transmissive substrate and the light non-transmissive
substrate, i.e., the inspection of the luminance unevenness in spite of the simple
structure by using the two illumination systems and the macro camera commonly used
therefor.
[0037] The mi.cro inspection unit 106 is the unit which inspects the pattern defect of the
substrate P tra,nsported by the transport system 108, i.e., for example, the minute defect
of the concave-convex structure for forming the pattern, the foreign matter adhered to
the substrate P, and the scratch originating from the steps. The micro inspection unit
106 comprises a transmitting light illumination for micro 124 and a non-transmitting
light illumination for micro 126 which serve as an illumination system for micro
(second irradiation system), and micro cameras 122 which serve as a detection system
for micro (second detection system). As shown in Fig. 2B, the four micro cameras 122
are arranged in the X direction. When the plurality of micro cameras 122 are aligned as
described above, then the entire area of the inspection objective can be thereby inspected
by means of one scanning, and the productivity can be improved by shortening the
inspection tact. The detection objective of the micro detection system is the area having
an areal size of 1 J.1m2 to 25 mm2
•
[0038] The transmitting light illumination for micro 124 is the illumination which is
15
used to inspect the light transmissive substrate, and the transmitting light illumination
for micro 124 is provided under or below the transport system 108. In this embodiment,
a line-shaped illumination, in which LEDs for emitting the light (second detection light)
having a wavelength of 400 nm to 800 nm are embedded in a frame in an array form in
the X direction, is used for the transmitting light ~umination for micro 124. In
particular, in order to obtain the sufficient light amount and perform the inspection
highly accurately, it is preferable to use a high luminance white line illumination. The
transmitting light illumination for micro 124 is attached rotatably about the center of a
rotary shaft 124a on a support base 124b so that the micro inspection position MI and
the angle of incidence of the illumination light with respect to the substrate P can be
regulated. The transmitting light illumination for micro 124 irradiates, with the light,
the back surface of the substrate P, i.e., the surface on which the concave-convex
structure is not formed, in the same manner as the case of the transmitting light
ill~ination for macro shown in Fig. 3A. The light, which comes into the inside of the
substrate P, is scattered and diffracted by the concave-convex pattern on the surface of
the substrate P. In any one of the transmitting light illumination for micro and the
transmitting light illumination for macro, it is preferable that the illumination light is
allowed to come at an angle of incidence of 20° to 60° with respect to the normal line of
the substrate from the side on which the concavities and convexities of the substrate do
not exist. If the substrate is irradiated from the concave-convex surface, then the light,
which is diffracted and scattered by the surface (concave-convex surface), is reflected by
the opposite surface (surface having no concavity and convexity), and hence any vivid
image is hardly obtained. If the light is allowed to come at an angle lower than 20°,
then the effect of diffraction and scattering, which is to be obtained by the concavities
and convexities, is weakened, and it is impossible to obtain any sufficient light amount.
If the light is allowed to come at an angle higher than 60°, it is impossible to obtain any
sufficient light amount on account of the loss caused by the reflection. The preferred
range of the angle of incidence also holds similarly for the non-transmitting light
illumination for micro and the non-transmitting light illumination for macro.
[0039] The scattered and diffracted lights, which come from the concave-convex
structure, are received by the micro cameras 122 which are installed over or above the
transport system 108 on the downstream side in the transport direction from the
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transmitting light illumination 124. The micro camera detects the relatively narrow
range at a high resolution. Therefore, it is preferable that the pixel size is 1 IJlll to 50
!Jlll. If the pixel size is below 1 J.llll, any clear image is not obtained due to the
insufficient light amount in some cases. In other cases, the depth of focus becomes
shallow, and the image is blurred by any slight undulation and/or any vibration caused
during the transport. If the pixel size exceeds 50 J.UD., it is feared that any minute defect
cannot be detected. For example, it is possible to use a CCD camera adjusted to provide
15 Jl.Illlpixel. In general, the micro camera 122 is arranged at the position at which the
primary diffracted light coming from the concave-convex pattern can be received. The
micro camera 122 is attached to a movement stage 122a by the aid of an arm 122b
having a rotary shaft. The movement stage 122a is slidably movable on a stage base
122c. Accordingly, the micro camera 122 can be moved in the X direction and the
optical axis direction of the micro camera 122. Further, it is possible to change the
inclination of the optical axis (light receiving angle) of the micro camera 122 by means
of the rotary shaft of the arm 122b.
[0040] The non-transmitting light illumination for micro 126 is the illumination which
is used to inspect the non-transmissive substrate. The non-transmitting light
illumination for micro 126 is provided on the support base 130 disposed over or above
the inspection position MA over or above the transport system 108. In this embodiment,
a line-shaped illumination, in which LEOs for emitting the light having a wavelength of
400 nm to 800 nm are embedded in an array form in the X direction, is used for the nontransmitting
light illumination for micro 126. The non-transmitting light illumination
for micro 126 is provided slidably on a guide 126a so that the position and the angle for
light irradiation can be regulated. The non-transmitting light illumination for micro 126
irradiates, with the light, the surface of the substrate P, i.e., the surface on which the
concave-convex pattern is formed, and the scattering and the diffraction are caused by
the concave-convex structure of the surface of the substrate P, in the same manner as the
non-transmitting light illumination for macro 116 shown in Fig. 3B. The scattered and
diffracted lights (reflected light) coming from the concave-convex structure are received
by the micro cameras 122.
[0041] It is preferable that any one of the cameras of the micro inspection unit 106 and
the macro inspection unit 104 is installed on the side of the concave-convex surface of
17
the substrate. Further, it is preferable that the image pickup direction generally resides
in the position at which the primary diffracted light coming from the concave-convex
pattern can be received, i.e., at 40° to goo from the normal line direction of the substrate.
If the image pickup is performed at an angle lower than 40°, there is such a tendency
that the effect of diffraction and scattering brought about by the concavities and
convexities is weakened, and it is impossible to obtain any sufficient light amount. If
the image pickup is performed at an angle higher than goo, there is such a tendency that
the effect of diffraction and scattering brought about by the concavities and convexities
is weakened, and it is impossible to obtain any sufficient light amount.
[0042] As described above, even when the transported substrate is light transmissive or
non-transmissive, the micro inspection unit 106 can inspect the minute defect of any
substrate by properly using the illumination systems. That is, the micro inspection unit
106 makes it possible to perform the both types of defect inspection of the light
transmissive substrate and the light non-transmissive substrate in spite of the simple
structure by using the two illumination systems and the micro cameras commonly used
therefor, in the same manner as the macro inspection unit 104. A marker 132 for
marking the defect portion of the substrate P detected by the micro inspection unit 106
and a driving system 132a therefor are provided between the transmitting light
illumination for macro 114 and the transmitting light illumination for micro 124 under
or below the transport system 10g. An ink-jet head or a magic ink can be used for the
marker 132.

[0043] Next, an explanation will be made about the operation of the inspection
apparatus 102 and an example of the substrate inspection method.
A. Inspection of light non-transmissive substrate
[0044] Fig. 4 shows an arrangement of the light non-transmissive substrate P as an
inspection objective, the macro camera 112, and the micro cameras 122 as viewed from
a position over or above the inspection apparatus 102. In this embodiment, when the
substrate P is inspected, the minute defect is firstly inspected by means of the micro
inspection unit 106. The control unit 111 turns ON the non-transmitting light
illumination for micro 126 (see Fig. 2A), and the control unit 111 controls the transport
system 1 og so that the substrate P is transported in the + Y direction toward the micro
18
detection position MI. When the substrate P passes over the micro detection position
MI on the travel route, the scattered light coming from the surface of the substrate P is
received by the four micro cameras 122. The intensity of the received light is inputted
into the control system 111 together with the coordinate position in the transport
direction of the substrate P. The control system 111 is provided with an image
processing unit 111a in which the light intensities received from the micro detection
position MI by the four micro cameras 122 are allowed to correspond in relation to each
of the coordinate positions on the substrate P (X coordinate position and Y coordinate
position). Thus, the micro inspection image, which represents the light intensity of the
entire substrate P, is synthesized by the image processing unit 111 a on the basis of the
light intensity in relation to each of the coordinate positions. The pixel positions of the
micro cameras 122 are previously allowed to correspond to the positions of the substrate
Pin the transport direction (Y direction) and the X direction perpendicular thereto.
[0045] When the micro inspection is completed as described above, then the control
system 111 subsequently turns OFF the non-transmitting light illumination for micro
126, and the control system 111 turns ON the non-transmitting light illumination for
macro 116 in place thereof. Further, the control system 111 controls the transport
system 108 so that the substrate P is moved in the direction (-Y direction) opposite to
the transport direction, i.e., on the travel return route of the movement route of the micro
inspection. When the substrate P passes over the macro detection position MA on the
travel route, the scattered light coming from the surface of the substrate P is received by
the macro camera 112. As described above, the resolution of the macro camera 112 is
lower than the resolution of the micro camera. However, the field of the macro camera
112 is wide, and hence the scattered light can be detected over the entire region in the X
direction of the substrate by using one camera. The intensity of the received light is
inputted into the control system 111 together with the coordinate position of the
substrate P in the transport direction. In the image processing unit 111a of the control
system 111, the light intensity received from the macro inspection position MA by the
macro camera 112 is allowed to correspond in relation to each of the coordinate
positions on the substrate P (positions in the transport direction (Y direction) and
positions in the direction (X direction) perpendicular thereto). Thus, the macro
inspection image, which represents the intensity of the light of the entire substrate P, is
19
synthesized by the image processing unit 111 a on the basis of the light intensity in
relation to each of the position coordinates.
B. Inspection of light transmissive substrate
[0046] When the substrate as the inspection objective is the light transmissive substrate,
then the transmitting light illumination for micro 124 is used in place of the nontransmitting
light illumination for micro 126, and the transmitting light illumination for
macro 114 is used in place of the non-transmitting light illumination for macro 116. In
the inspection operation, the minute defect is firstly inspected by means of the micro
inspection unit 106, while moving the substrate P in the transport direction in the same
manner as the case shown in Fig. 4. That is, the control system 111 turns ON the
transmitting light illumination for micro 124 (see Fig. 2A), and the control system 111
controls the transport system 108 so that the substrate P is transported in the + Y
direction toward the micro detection position MI. When the substrate P passes over the
micro detection position MI, the scattered light coming from the surface of the substrate
P is received by the four micro cameras 122. The intensity of the received light is
inputted into the control system 111 together with the coordinate position in the
transport direction of the substrate P. In the image processing unit 111a of the control
system 111, the light intensities received from the micro detection position MI by the
four micro cameras 122 are allowed to correspond in relation to each of the coordinate
positions on the substrate P (X coordinate position and Y coordinate position). Thus,
the micro inspection image, which represents the light intensity of the entire substrate P,
is synthesized by the image processing unit 111a on the basis of the light intensity in
relation to each of the coordinate positions. Fig. 5A shows an example of the
synthesized micro inspection image. Fig. 5A shows the micro inspection image
obtained from a substrate having a concave-convex pattern formed by using a sol-gel
material on a glass substrate as described later on.
[0047] When the micro inspection is completed, then the control system 111
subsequently turns OFF the non-transmitting light illumination for micro 126, and the
control system 111 turns ON the transmitting light illumination for macro 114 in place
thereof. Further, the control system 111 controls the transport system 108 so that the
substrate Pis moved on the travel return route(-Y direction) of the movement route of
the micro inspection. When the substrate P passes over the macro detection position
20
MA, the scattered light coming from the surface of the substrate P is received by the
macro camera 112. The intensity of the received light is inputted into the control system
111 together with the coordinate position of the substrate P in the transport direction. In
the control system 111, the light intensity received from the macro inspecqon position
MA by the macro camera 112 is allowed to correspond in relation to each of the
coordinate positions on the substrate P. Thus, the macro inspection image, which
represents the intensity of the light of the entire substrate P, is synthesized by the image
processing unit 111a of the control system 111 on the basis of the light intensity of each
of the position coordinates. Fig. 5B shows an example of the synthesized macro
inspection image. Fig. 5B shows the macro inspection image obtained from a substrate
having a concave-convex pattern formed by using a sol-gel material on a glass substrate
as described later on.

[0048] The luminance of each of the pixels of the micro inspection image synthesized
by the image processing unit 111a in the inspection step described above is evaluated by
the control system 111. If any part or portion, in which the luminance is higher or lower
than a certain luminance , is present and the size of the part or portion is not less than a
predetermined size, then the concerning part or portion is judged as the defect, and the
coordinate of the defect and the image therearound are stored in a storage unit 111 b of
the control system 111. Further, the coordinate, on which the defect exists, is fed to the
marker 132. The transport system 108 and the marker driving system 132a are driven to
move the marker 132 while confronting the defect portion of the substrate P. A mark is
affixed to the defect portion by the marker 132 from the back surface of the substrate
(marking step). It is not necessarily indispensable to perform the marking step.
However, the marking step is useful, for example, in order to specify the position of the
defect portion, for example, when the defect position is analyzed. Further, the
luminance of each of the pixels of the macro inspection image synthesized by the image
processing unit 111 a in the inspection step described above is evaluated by the control
system 111. If the portion, in which the luminance is higher or lower than a certain
luminance, has the areal size which is smaller than a certain areal size, it is judged that
the product is a non-defective (satisfactory) product. If the portion has the areal size
which is larger than the certain areal size, it is judged that the product is a defective
21
product.

[0049] If it is judged in the judging step that the luminance unevenness and the defect
are within the desired ranges, the organic EL element is produced in accordance with the
process described later on by using the substrate. If it is judged that the luminance
unevenness or the defect is without the desired range, the aftertreatment is applied. In
the aftertreatment, it is analyzed whether the defect (luminance unevenness) of the
substrate is caused by the dust, the scratch, the periodic error, or the random error. If the
defect is caused by any adhered matter such as the dust or the like, the repair can be
performed, for example, by blowing off the adhered matter by applying the pressurized
air to the substrate surface. After that, the inspection as described above is performed
again. If the inspection as described above is performed for a plurality of substrates in
accordance with the continuous system or the batch system, it is possible to provide
such a step that those in which the ratio of the maximum value with respect to the
minimum value, the scattering intensity difference, or the average pixel value is within
the desired range are distinguished from those in which the ratio of the maximum value
with respect to the minimum value, the scattering intensity difference, or the average
pixel value is without the range, on the basis of the inspection result. Those in which
the. ratio of the maximum value with respect to the minimum value, the scattering
intensity difference, or the average pixel value is within the range can be supplied, for
example, to a production line for the organic EL element or the like to successively
produce the organic EL element. Those in which the ratio of the maximum value with
respect to the minimum value, the scattering intensity difference, or the average pixel
value is without the range can be subjected to the defect analysis or can be discarded all
at once.

[0050] An explanation will be made below about the step of manufacturing (preparing)
the substrate used for the inspection apparatus of the present invention and the
inspection method based on the use of the same. The inspection apparatus of the
present invention and the inspection method based on the use of the same are
advantageous, for example, for the process for producing the light transmissive substrate
having the concave-convex pattern when the step of manufacturing a light non-
22
transmissive mold or replica for producing such a light transmissive substrate in
accordance with the transfer process is present. That is, as described above, in the
inspection apparatus and the inspection method of the present invention, the
illumination system can be switched depending on the light transmission characteristic
of the substrate as the inspection objective to inspect the luminance unevenness and the
pattern defect. Therefore, it is possible to employ, as the inspection objective, not only
the light transmissive substrate having the concave-convex pattern provided as the
product but also any one of the concave-convex patterns of the light non-transmissive
mold and the replica for producing the same. An explanation will be made below as
exemplified by the production process for procuring the light transmissive substrate
used for the light scattering substrate of the organic EL by way of example.
[0051] In order to produce the substrate having the irregular concave-convex surface, it
is preferable to use a method in which the self-organization or self-assembly (micro
phase separation) of block copolymer is utilized as described in Japanese Patent
Application No. 2011-006487 filed by the present applicant (hereinafter referred to as
"BCP (Block Copolymer) method" as appropriate) and a method in which concavities
and convexities are formed by using wrinkles on the polymer surface by heating and
cooling a polymer fJ.lm on a vapor-deposited fllm as disclosed in PCT/JP2010/062110
(W02011/007878A1) ftled by the present applic~t (hereinafter referred to as "BKL
(Buckling) method" as appropriate) as explained. below. The respective methods will be
explained.
A. Production of substrate by BCP method
[0052] An explanation will be made with reference to Figs. 6 to 9 about the production
of the substrate by means of the BCP method.
[Preparation step of block copolymer solution]
[0053] The block copolymer used for the BCP method includes at least a first polymer
segment composed of a first homopolymer and a second polymer segment composed of
a second homopolymer different from the fist homopolymer. The second homopolymer
desirably has a solubility parameter which is higher than a solubility parameter of the
first homopolymer by 0.1 (cal/cm3
)
112 to 10 (cal/cm3
)
112
• In a case that the difference in
the solubility parameter between the first and second homopolymers is less than 0.1
( cal/cm3
)
112
, it is difficult to form a regular micro phase separation structure of the block
23
copolymer. In a case that the difference exceeds 10 (caVcm3
)
112
, it is difficult to prepare
a uniform or homogeneous solution of the block copolymer.
[0054] Examples of monomers serving as raw materials of homopolymers usable as the
first homopolymer and the second homopolymer include styrene, methylstyrene,
propylstyrene, butylstyrene, hexylstyrene, octylstyrene, methoxystyrene, ethylene,
propylene, butene, hexene, acrylonitrile, acrylamide, methyl methacrylate, ethyl
methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl
methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl
acrylate, octyl acrylate, methacrylic acid, acrylic acid, hydroxyethyl methacrylate,
hydroxyethyl acrylate, ethylene oxide, propylene oxide, dimethylsiloxane, lactic acid,
vinylpyridine, hydroxystyrene, styrenesulfonate, isoprene, butadiene, e-caprolactone,
isopropylacrylamide, vinyl chloride, ethylene terephthalate, tetrafluoroethylene, and
vinyl alcohol. Among these monomers, styrene, methyl methacrylate, ethylene oxide,
butadiene, isoprene, vinylpyridine, and lactic acid are preferably used from the
viewpoints that the formation of phase separation easily occurs, and that concavities and
convexities are easily formed by means of the etching.
[0055] Further, examples of a combination of the first homopolymer and the second
homopolymer may include combinations of two selected from the group consisting of a
styrene-based polymer (more pref~rably, polystyrene), polyalkyl methacrylate (more
preferably, polymethyl methacrylate), polyethylene oxide, polybutadiene, polyisoprene,
polyvinylpyridine, and polylactic acid. Among these combinations, a combination of
the styrene-based polymer and polyalkyl methacrylate, a combination of the styrenebased
polymer and polyethylene oxide, a combination of the styrene-based polymer and
polyisoprene, and a combination of the styrene-based polymer and polybutadiene are
more preferable, and the combination of the styrene-based polymer and polymethyl
methacrylate, the combination of the styrene-based polymer and polyisoprene, and the
combination of the styrene-based polymer and polybutadiene are particularly preferable,
from the viewpoints that the depth of the concavities and convexities formed in the
block copolymer can be further deepened by preferentially removing one homopolymer
by means of the etching process. A combination of polystyrene (PS) and polymethyl
methacrylate (PMMA) is more preferred.
[0056] The number average molecular weight (Mn) of the block copolymer is preferably
24
not less than 500,000, and more preferably not less than 1,000,000, and particularly
preferably in a range of 1,000,000 to 5,000,000. In a case that the number average
molecular weight is less than 500,000, the average pitch of the concavities and
convexities formed by the micro phase separation structure of the block copolymer is so
small that the average pitch of the concavities and convexities of the obtained
diffraction grating becomes insufficient. Especially, in a case of the diffraction grating
used for the organic EL, it is necessary to diffract the illumination light over a range of
wavelength of the visible region, and thus the average pitch is desirably in a range of
100 nm to 1,500 nm. In view of this point, the number average molecular weight (Mn)
of the block copolymer is preferably not less than 500,000. On the other hand,
according to an experiment performed by the present applicant, as described later on, the
following fact has been revealed. That is, when the number average molecular weight
(Mn) of the block copolymer is not less than 500,000, if the second heating step is not
performed after the etching step, then it is difficult to obtain any desired concaveconvex
pattern by means of the electroforming.
[0057] The molecular weight distribution (Mw!Mn) of the block copolymer is
preferably not more than 1.5, and is more preferably in a range of 1.0 to 1.35. In a case
that the molecular weight distribution as described above exceeds 1.5, it is not easy to
form the regular mi~ro phase separation structure of the block copolymer.
[0058] Note that the number average molecular weight (Mn) and the weight average
molecular weight (Mw) of the block copolymer are values measured by the gel
permeation chromatography (GPC) and converted to the molecular weights of standard
polystyrene.
[0059] In the block copolymer, the volume ratio between the first polymer segment and
the second polymer segment (the first polymer segment: the second polymer segment) is
desirably in a range of 3:7 to 7:3 and more preferably 4:6 to 6:4 in order to generate a
lamella structure by the self-organization or self-assembly. In a case that the volume
ratio is out of the range described above, it is difficult to form a concave-convex pattern
(concavity and convexity pattern) resulting from the lamella structure.
[0060] The block copolymer solution used for the BCP method is prepared by
dissolving the block copolymer in a solvent. Examples of the solvent include aliphatic
hydrocarbons such as hexane, heptane, octane, decane, and cyclohexane; aromatic
25
hydrocarbons such as benzene, toluene, xylene, and mesitylene; ethers such as diethyl
ether, tetrahydrofuran, and dioxane; ketones such as acetone, methyl ethyl ketone,
isophorone, and cyclohexanone; ether alcohols such as butoxyethyl ether, hexyloxyethyl
alcohol, methoxy-2-propanol, and benzyloxyethanol; glycol ethers such as ethylene
glycol dimethyl ether, diethylene glycol dimethyl ether, triglyme, propylene glycol
monomethyl ether, and propylene glycol monomethyl ether acetate; esters such as ethyl
acetate, ethyl lactate, and y-butyrolactone; phenols such as phenol and chlorophenol;
amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and Nmethylpyrrolidone;
halogen-containing solvents such as chloroform, methylene chloride,
tetrachloroethane, monochlorobenzene, and dichlorobenzene; hetero-element containing
compounds such as carbon disulfide; and mixture solvents thereof. The percentage
content of the block copolymer in the block copolymer solution is preferably in a range
of 0.1% by mass to 15% by mass, and more preferably in a range of 0.3% by mass to 5%
by mass, relative to 100% by mass of the block copolymer solution.
[0061] In addition, the block copolymer solution may further contain, for example,
another homopolymer (a homopolymer other than the first homopolymer and the second
homopolymer in the block copolymer contained in the solution: for example, in a case
that the combination of the first homopolymer and the second homopolymer in the
bloc~ copolymer is the combination of polystyrene and polymethyl methacrylate, the
another homopolymer may be any kind of homopolymer other than polystyrene and
polymethyl methacrylate), a surfactant, an ionic compound, an antifoaming agent, and a
leveling agent.
[0062] When the another homopolymer is contained, it is thereby possible to improve
the micro phase separation structure of the block copolymer. For example, it is possible
to use polyalkylene oxide in order to further deepen the depth of the concavities and
convexities formed by the micro phase separation structure. As the polyalkylene oxide
as described above, polyethylene oxide or polypropylene oxide is more preferred, and
polyethylene oxide is particularly preferred. Further, as the polyethylene oxide as
described above, one represented by the following formula is preferred:
IIC>- (~lfz-~Ilz-C>)n-II
[in the formula, "n" represents an integer in a range of 10 to 5,000 (more preferably an
integer in a range of 50 to 1 ,000, and further preferably an integer in a range of 50 to
26
500)].
[0063] If the value of n as described above is less than the lower limit described above,
then the molecular weight is too low, and the substance is lost, for example, by the
volatilization and/or the evaporation on account of the heating process at a high
temperature, and the effect obtained by containing the another homopolymer is scarce.
If the value of n exceeds the upper limit, then the molecular weight is too high, and the
molecular motility is low. Therefore, the velocity of phase separation is slowed down,
and any harmful influence is exerted on the formation of the micro. phase separation
structure.
[0064] Further, the number average molecular weight (Mn) of the another homopolymer
as described above is preferably in a range of 460 to 220,000, and is more preferably in
a range of 2,200 to 46,000. If the number average molecular weight is less than the
lower limit, then the molecular weight is too low, the substance is lost, for example, by
the volatilization and/or the evaporation on account of the heating process at a high
temperature, and the effect obtained by containing the another homopolymer is scarce.
If the number average molecular weight exceeds the upper limit, then the molecular
weight is too high, and the molecular motility is low. Therefore, the velocity of phase
separation is slowed down, and any harmful influence is exerted on the formation of the
micro phase separation structure.
[0065] The molecular weight distribution (Mw/Mn) of the another homopolymer as
described above is preferably not more than 1.5, and more preferably in a range of 1.0 to
1.3. In a case that the molecular weight distribution exceeds the upper limit, it is
difficult to maintain the uniformity of shape of the micro phase separation. Note that
the number average molecular weight (Mn) and the weight average molecular weight
(Mw) as described above are values measured by the gel permeation chromatography
(GPC) and converted to molecular weights of standard polystyrene.
[0066] Further, when the another homopolymer is used in the BCP method, it is
preferable that the combination of the first homopolymer and the second homopolymer
in the block copolymer is the combination of polystyrene and polymethyl methacrylate
(polystyrene-polymethyl methacrylate), and the another homopolymer is polyalkylene
oxide. By using a polystyrene-polymethyl methacrylate block copolymer and
polyalkylene oxide in combination as described above, the orientation in the vertical
27
direction is further improved, thereby making it possible to further increase the depths
of the concavities and convexities on the surface, and to shorten the heating process
time or the solvent annealing process time described later on during the production.
[0067] When the another homopolymer is contained in the block copolymer solution
described above, the total percentage content of the block copolymer and the another
homopolymer is preferably in a range of 0.1% by mass to 15% by mass, and more
preferably in a range of 0.3% by mass to 5% by mass, in the block copolymer solution.
In a case that the total percentage content is less than the lower limit, it is not easy to
uniformly apply the solution on a base member (coat a base member with the solution)
in order to attain a film of which thickness is sufficient to obtain a necessary film
thickness. In a case that the total percentage content exceeds the upper limit, it is
relatively difficult to prepare a solution in which the block copolymer and the another
homopolymer are uniformly dissolved in the solvent.
[0068] When the another homopolymer is used, it is preferable that the content is not
more than 100 parts by mass with respect to 100 parts by mass of the block copolymer.
It is more preferable that the content is in a range of 5 parts by mass to 100 parts by
mass. If the content of the another homopolymer as described above is less than the
lower limit, the effect obtained by containing the another homopolymer is scarce. When
polyalkylene oxide is used as the another homopolymer, the content thereof is more
preferably in a range of 5 parts by mass to 70 parts by mass. If the content of
polyalkylene oxide exceeds 100 parts by mass with respect to 100 parts by mass of the
block copolymer, the concave-convex pattern, which is formed by the phase separation
of the block copolymer, collapses with ease. On the other hand, if the content of
polyalkylene oxide exceeds 70 parts by mass, polyalkylene oxide is deposited in some
cases.
[0069] In a case that the surfactant is used, the content of the surfactant is preferably not
more than 10 parts by mass, relative to 100 parts by mass of the block copolymer.
Further, in a case that the ionic compound is used, the content of the ionic compound is
preferably not more than 10 parts by mass, relative to 100 parts by mass of the block
copolymer.
[Block copolymer solution coating step]
[0070] According to the substrate production method based on the use of the BCP
28
method, as shown in Fig. 6A, the block copolymer solution prepared as described above
is applied onto a base member 10 (a base member 10 is coated with the block copolymer
solution) to form a thin film 30. The base member 10 is not especially limited.
However, the base member 10 includes, for example, resin substrates of resins such as
polyimide, polyphenylene sulfide (PPS), polyphenylene oxide, polyether ketone,
polyethylene naphthalate, polyethylene terephthalate, polyarylate, triacetyl cellulose, and
polycycloolefm; inorganic substrates such as glass, octadecyldimethyl chlorosilane
(ODS) treated glass, octadecyl trichlorosilane (OTS) treated glass, organo silicate
treated glass, glass substrates treated with a silane coupling agent, and silicon substrates;
and metal substrates of metals such as aluminum, iron, and copper. Further, the base
member 10 may be subjected to a surface treatment such as an orientation treatment, etc.
For example, the organo silicate treated glass can be prepared by coating a glass with a
methyl isobutyl ketone (MIBK) solution of methyl trimethoxysilane (MTMS) and 1,2-
bis(trimethoxysilyl) ethane (BTMSE), and then performing the heating process therefor.
Each of the octadecyldimethyl chlorosilane treated glass and octadecyl trichlorosilane
treated glass can be prepared by such a method including immersing a glass in a heptane
solution of one of octadecyldimethyl chlorosilane and octadecyl trichlorosilane
beforehand, and washing out the unreacted portion from the glass thereafter. In such a
manner, it is allowable to perform the surface treatment for a surface of the substrate
such as the glass with a primer layer of octadecyldimethyl chlorosilane, organo silicate,
etc., or to perform the silane coupling treatment for the substrate surface with a general
silane coupling agent, thereby making it possible to improve the adhesion property of
the block copolymer to the substrate. In a case that the adhesion property is not
sufficient, the block copolymer drops off or detaches (peels off or exfoliates) from the
substrate during the electroforming, which in turn adversely affects the production of a
mold for transferring. Note that when the surface of the substrate such as glass or the
like is treated with ODS, organosilicate or the like, then the micro phase separation
structure, which includes, for example, the lamella structure, the cylinder structure, and
the spherical structure, is easily arranged perpendicularly with respect to the surface in
the heating step described later on, for the following reason. That is, the interface
energy different is decreased between the block copolymer component and the substrate
surface, and thus the domains of the respective blocks for constructing the block
29
copolymer are easily oriented perpendicularly.
[0071] The method for applying the block copolymer solution onto the base member
(coating the base member with the block copolymer) is not particularly limited, for
which it is allowable to employ, for example, the spin coating method, spray coating
method, dip coating method, dropping method, gravure printing method, screen printing
method, relief printing method, die coating method, curtain coating method, and ink-jet
method.
[0072] As for the thickness of the thin film 30 of the block copolymer, as will be
described later on, the thickness of a coating film after being dried is preferably in a
range of 10 nm to 3,000 nm, and more preferably in a range of 50 nm to 500 nm.
[Drying step]
[0073] Mter the base member 10 is coated with the block copolymer solution to form
the thin film 30, the thin film 30 on the base member 10 is dried. The drying can be
performed in an atmosphere of the atmospheric air. The temperature for drying the thin
film 30 is not particularly limited, provided that the solvent can be removed from the
thin film 30. For example, the drying temperature is preferably in a range of l0°C to
200°C, and more preferably in a range of 20°C to 100°C. Note that the drying step
starts the formation of micro phase separation structure of the block copolymer, which
results in appearance of concavities and convexities on the surface of the thin film 30 in
some cases.
[First heating step]
[0074] Mter the drying step, the thin fllm 30 is heated at a temperature of not less than
the glass transition temperature (Tg) of the block copolymer (first heating step or
annealing step). The heating step (example of the step of generating the micro phase
separation structure) allows the self-organization or self-assembly of the block
copolymer to proceed. As shown in Fig. 6B, the block copolymer is subjected to the
micro phase separation into portions of a first polymer segment 32 and a second
polymer segment 34. If the heating temperature is less than the glass transition
temperature of the block copolymer, then the molecular motility of the polymer is low,
and the self-organization or self-assembly of the block copolymer does not proceed
sufficiently. The micro phase separation structure cannot be formed sufficiently, or the
heating time, which is required to sufficiently generate the micro phase separation
30
structure, is prolonged. Further, the upper limit of the heating temperature is not
specifically limited, provided that the heating temperature is a temperature at which the
block copolymer is not thermally decomposed. The first heating step can be performed
in the atmosphere of the atmospheric air by using, for example, an oven. Note that the
heating temperature may be gradually raised to continuously perform the drying step and
the heating step. By doing so, the drying step is included in the heating step.
[Etching step]
[0075] The etching process is performed for the thin film 30 after the first heating step.
The molecular structure of the first polymer segment 32 is different from that of the
second polymer segment 34. Therefore, the easiness of etching also differs
therebetween. Therefore, it is possible to selectively remove the polymer segment, i.e.,
one polymer segment (second polymer segment 34) for constructing the block
copolymer, by means of the etching process depending on the type of the homopolymer.
As shown in Fig. 6C, the second polymer segment 34 is removed from the micro phase
separation structure by means of the etching process, and the conspicuous concaveconvex
structure appears in the coating film. Those adoptable for the etching process
described above include, for example, the reactive ion etching method, the ozone
oxidization method, the hydrolysis method, the metal ion dyeing (staining) method, and
the ultraviolet etching method. Further, as for the etching process, it is also allowable to
adopt a method in which the covalent bond of the block copolymer is treated with at .
least one selected from the group consisting of acids, bases, and reducing agents to cut
or cleave the covalent bond, and then the coating ftlm formed with the micro phase
separation structure is cleaned or washed, for example, with a solvent for dissolving
only one polymer segment so that only the one polymer segment is removed thereby
while maintaining the micro phase separation structure. In the embodiment described
later on, the ultraviolet etching is used, for example, in view of the easiness of the
operation.
[Second heating step]
[0076] The second heating or annealing process is applied to the concave-convex
structure 36 of the thin film 30 obtained by the etching step described above. The
heating temperature in the second heating process is desirably not less than the glass
transition temperature of the first polymer segment 32 allowed to remain after the
31
etching, i.e., not less than the glass transition temperature of the first homopolymer. For
example, the heating temperature is desirably not less than the glass transition
temperature of the first homopolymer and not more than a temperature which is higher
than the glass transition temperature of the first homopolymer by 70°C. If the heating
temperature is less than the glass transition temperature of the first homopolymer, then
the desired concave-convex structure, i.e., the smooth mountain-like structure is not
obtained after the electroforming, or a long time is required for the heating. If the
heating temperature is considerably higher the glass transition temperature of the first
homopolymer, then the first polymer segment 32 is melted, and/or the shape collapses
greatly, which is not preferred. In view of the above, it is desirable that the heating is
performed within a range from the glass transition temperature to the temperature higher
than the glass transition temperature by about 70°C. The second heating process can be
also performed in the atmosphere of the atmospheric air by using, for example, an oven,
in the same manner as the first heating process.
[0077] According to an experiment performed by the present inventors, the following
fact has been revealed. That is, any desired transfer pattern is hardly obtained, although
the concave-convex structure is transferred to a metal mold by means of the
electroforming as described later on by using, as a master (master block or mold), the
concave-convex structure 36 of the coating fllm obtained by the etching step. In
particular, this problem is more conspicuous when the molecular weight of the block
copolymer is larger. As described above, the molecular weight of the block copolymer
deeply relates to the micro phase separation structure, and consequently the pitch of the
diffraction grating obtained therefrom. Therefore, when the diffraction grating is used
for the way of use of the organic EL element or the like, it is necessary to provide the
pitch distribution so that the diffraction is caused in the wavelength region which is
wide or extensive like the visible region and which includes the wavelength band having
relatively long wavelengths. In order to realize such a situation, it is necessary to
reliably obtain the concave-convex structure having the desired pitch distribution as
described above by means of the electroforming, even in the case of the use of the block
copolymer having a relatively high molecular weight. In the present invention, the
concave-convex structure, which is obtained by the etching, is subjected to the heating
process. Thus, the metal substrate (mold), in which the concave-convex structure is
32
sufficiently reflected, can be obtained even in the case of the electroforming step
performed thereafter.
[0078] The reason thereof is considered as follows by the present inventors. The
concave-convex structure 36 after the etching is considered to have a complicated crosssectional
structure in which the grooves defined by the concave-convex structure have
rough side surfaces and the concavities and convexities (including overhangs) are
generated in the direction perpendicular to the thickness direction. The following three
problems arise on account of the complicated cross-sectional structure as described
above.
[0079] i) The portion, to which the seed layer for the electroforming does not adhere, is
generated in the complicated cross-sectional structure, and it becomes difficult to
uniformly accumulate the metal layer by means of the electroforming. As a result, an
obtained metal substrate has a low mechanical strength, which causes the occurrence of
any defect including, for example, the deformation of the metal substrate and the pattern
deficiency.
[0080] ii) In the case of the electroforming (electroplating), the thickness of plating of
each portion differs depending on the shape of the object subjected to the plating. In
particular, the plating metal is easily attracted by the convexity (protrusion) and the
projecting comer of the object, and the plating metal is 4ardly attracted by the concavity
(recess) and the recessed (dented) portion. Also from the reason as described above, the
cross-sectional structure having the complicated concavities and convexities after the
etching makes it difficult to obtain an electroforming film having a uniform film
thickness.
[0081] iii) Even when the complicated cross-sectional structure as described above can
be transferred to the metal substrate by means of the electroforrning, if it is intended to
transfer the concave-convex shape by pressing the metal substrate against a curable
resin, then the curable resin enters the gaps of the complicated cross-sectional structure
of the metal substrate, and hence the metal substrate cannot be exfoliated (released or
peeled off) from the resin after the curing, or any portion of the metal substrate having a
weak strength is broken to cause the pattern deficiency. Note that in the conventional
technique, in order to solve this problem, the transfer is repeatedly performed with
polydimethylsiloxane (PDMS).
33
[0082] In the BCP method, the concave-convex structure after the etching is heated, and
thus the first polymer segment 32 for constructing the side surface of the groove is
subjected to the annealing process. As conceptually shown in Fig. 6D, the crosssectional
shape defmed by the frrst polymer segment 32 is formed into a mountain-like
shape which is composed of relatively smooth inclined surfaces and which is tapered
upwardly from the base member (referred to as "mountain-like structure" in this patent
application). In the case of the mountain-like structure as described above, no overhang
appears. The metal layer, which is accumulated in the first polymer segment 32, is
replicated or duplicated into a reversed pattern (inverted pattern) thereof. Therefore, the
exfoliation is performed with ease. It has been clarified that the three problems
described above can be solved in accordance with the action of the second heating step
as described above. The present applicant has revealed the following fact. That is,
when a photograph of scanning electron microscope (SEM) is taken to show a crosssectional
structure of a metal substrate formed by the Ni electroforming from a concaveconvex
structure obtained by performing the heating process after the etching process
for the block copolymer, then the concavities and convexities are smooth, the
convexities provide gentle mountain-like shapes, and any overhang is not observed at
all. On the other hand, in the case of an SEM photograph to show a cross-sectional
structure of a metal substrate formed by t_he Ni (nickel) electroforming from a concaveconvex
structure obtained without perfol,1ning the second heating process after the
etching process for the block copolymer, the following situation has been confrrmed.
That is, the Ni portion forms grooves having complicated shapes including overhang
structures, and the resin enters the inside thereof.
[0083] The mountain-like structure 38 is formed by performing the first heating step,
the etching step, and the second heating step as described above. However, in place
thereof, it is also allowable to form a wave-like structure in accordance with the solvent
annealing step explained below. In this case, in the preparation step for the block
copolymer solution described above, the volume ratio between the first polymer
segment and the second polymer segment in the block copolymer (first polymer
segment: second polymer segment) is preferably within a range of 4:6 to 6:4 and more
preferably about 5:5 in order to generate the horizontal cylinder structure by means of
the self-organization or self-assembly as described later on. If the volume ratio is
34
without the range as described above, then it is difficult to form the concave-convex
pattern resulting from the horizontal cylinder structure, and there is such a tendency that
a spherical or vertical cylinder structure appears.
[Solvent annealing s~ep]
[0084] After the drying step described above, the thin film 30 is subjected to the solvent
annealing process (solvent phase-separation process) under an atmosphere of the vapor
of an organic solvent so that a phase separation structure of the block copolymer is
formed inside the thin film 30. With this solvent annealing process, the selforganization
of the block copolymer is advanced, and the block copolymer undergoes
the micro phase separation into a portion corresponding to a first polymer segment 32
and a portion corresponding to a second polymer segment 34 as shown in Fig. 7 A.
[0085] For example, the solvent annealing process can be carried out by providing an
atmosphere of the vapor of organic solvent (organic solvent vapor) inside a tightly
sealable container such as a desiccator, and exposing the thin film 30 as the objective
under this atmosphere. The organic solvent to be used in the solvent annealing process
is preferably an organic solvent of which boiling point is in a range of 20°C to l20°C. It
is possible to use, for example, chloroform, dichloromethane, toluene, tetrahydrofuran
(THF), acetone, carbon disulfide, and mixture solvents thereof. Among these solvents,
it is preferable to use chlo~oform, dichloromethane, acetone, a mixture solvent of
acetone/carbon disulfide ..
[0086] The concentration of the organic solvent vapor is preferably high for the purpose
of promoting the phase separation of the block copolymer, which is desirably saturated
vapor pressure, wherein the concentration is controlled or managed relatively easily as
well. For example, in a case that the organic solvent is chloroform, the saturated vapor
amount (quantity) is known to be in a range of 0.4 g/1 to 2.5 g/1 at room temperature
(0°C to 45°C). As for the atmosphere temperature of the solvent annealing, it is
appropriate that the process is performed at 0°C to 45°C. If the temperature is higher
than 45°C, then the concave-convex structure formed on the thin film is blunt or dull
(loosened), and the concave-convex structure collapses with ease. In an environment
lower than 0°C, then the organic solvent is hardly evaporated, and the phase separation
of the block copolymer hardly occurs. The treatment time of the solvent annealing
process may be 6 hours to 168 hours, preferably 12 hours to 48 hours, and more
35
preferably 12 hours to 36 hours. If the time of the solvent annealing process is
excessively long, there is such a tendency that the another homopolymer is deposited on
the surface of the applied film (coating film) and/or the concave-convex shape is
collapsed Ooosened). On the other hand, if the time of the annealing process is
excessively short, then the grooves of the concave-convex structure are shallow, and the
diffniction effect is insufficient when the diffraction grating is manufactured by using
the mold.
[0087] Normally, the following is known as a general rule. In a case that the mixing
ratio between the first homopolymer and the second homopolymer for constructing the
block copolymer is even (5:5) or approximately even, a phase separation structure of the
lamella type appears by the thermal annealing process. In a case that the mixing ratio is
approximately 3:7, a cylinder structure appears. In a case that the mixing ratio is
approximately 2:8, a spherical structure appears. However, the present applicant has
found out that when the solvent annealing process is performed, then the phase
separation occurs while generating a cylinder structure in the horizontal direction even
in a case that the mixing ratio of the frrst homopolymer and the second homopolymer
for constructing the block copolymer is in a range of 4:6 to 6:4. Although the reason for
the above phenomenon is not clear, the present applicant considers as follows. That is,
the organic. solvent permeates into one of the homopolymers to cause one of the
homopolymers to swell. As a result, the apparent volume ratio between the frrst
homopolymer and the second homopolymer is different from the actual mixing ratio
between the frrst homopolymer and the second homopolymer.
[0088] In the horizontal cylinder structure, a first homopolymer 32 is present in a layer
of a second homopolymer 34, and the frrst homopolymer 32 is oriented in a form of
cylinders to extend in a direction substantially parallel to the surface of the base member
10, as shown in Fig. 7 A. As a result, a surface (top) layer portion of the second
homopolymer 34 is smoothly raised or bulged to form a wave-like shape, at portions at
which the first homopolymer 32 is present. Note that it is allowable that the cylinderlike
arrangement, in which the frrst homopolymer 32 extends in the direction
substantially parallel to the surface of the base member 10, is formed in a plurality of
layers (plurality of tiers or stages) in a direction (height direction) perpendicular to the
surface of the base member lO as shown in Fig. 78. The raised or bulged wave-like
36
structure can be utilized as it is as a concave-convex pattern of an optical substrate such
as a diffraction grating or the like. Accordingly. unlike the case of phase separation
brought about by the thermal annealing. there is no need to remove one of the
homopolymers by means of the etching after the phase separation. Note that a vertical
cylli;lder structure or a spherical structure may be included in a part of the horizontal
cylinder structure.
[0089] As conceptually shown in Fig. 7 A, the surlace shape, which is defined by the
polymer segment 34 by means of the solvent annealing process. is composed of
relatively smooth and sloped (inclined) surlaces, and the surlace shape forms a wavelike
shape in a direction upward from the base member (referred to as "wave-like shape"
in this patent application as appropriate). In the case of the wave-like shape as
described above, there is no overhang. The metal layer, which is accumulated on the
wave-like structure 38a as described above, is subjected to the duplication (replication)
into a reversed pattern (inverted pattern) thereof. and hence the metal layer is easily
releasable (peelable).
[0090] In the solvent annealing process, it is unnecessary to perform the etching process
and the second heating step described above. Therefore, it is possible to simplify the
substrate manufacturing (preparation) process. Further, the etching process involves
such a problem that the dirt and the dust easily appear on the substrate due to the use of .
the etching solution and the removal of one of the homopolymers. However, the etching
process is unnecessary owing to the solvent annealing process, and hence the foregoing
problem is dissolved as well. It is possible to obtain the substrate on which any foreign
matter scarcely adheres.
[0091] Further, it is also allowable to apply the heating process to the concave-convex
structure of the thin film 38a obtained by the solvent annealing process. The wave-like
concave-convex structure has been already formed by the solvent annealing process.
Therefore, the heating process sometimes loosens the formed concave-convex structure,
and the heating process is not necessarily indispensable. The heating process is
sometimes effective when any protrusion is formed on a part of the surface of the
concave-convex structure after the solvent annealing process on account of any cause or
when it is intended to adjust the cycle (period) and/or the height of the concave-convex
structure. For example, the heating temperature can be not less than the glass transition
37
temperatures of the first and second polymer segments 32, 34. For example, the heating
temperature can be not less than the glass transition temperatures of the homopolymers
and not more than a temperature higher than the glass transition temperatures by 70°C.
The heating process can be performed in the atmosphere of the atmospheric air by using,
for example, an oven.
[0092] Thus, the base member 10, which has the mountain-like structure 38 obtained in
the second heating step or the wave-like structure 38a obtained in the solvent annealing
step, is the inspection objective for the inspection apparatus and the inspection method
of the present invention. Further, the base member 10 is used as the maser for the
transfer in the steps performed thereafter. The average pitch of the concavities and
convexities to represent the mountain-like structure 38 or the wave-like structure 38a is
preferably in a range of 100 nm to 1,500 nm, and more preferably 200 nm to 1,200 nm.
If the average pitch of the concavities and convexities is less than the lower limit, then
the pitch is too small with respect to the wavelength of the visible light, and hence the
diffraction of the visible light, which is required for the diffraction grating obtained by
using such a master block (mold), is hardly caused. If the average pitch exceeds the
upper limit, then the diffraction angle of the diffraction grating obtained by using such a
master block (mold) is decreased, and it is impossible to sufficiently exhibit the function
as the diffraction grating. The average pitch of the concavities and convexities can be
determined as follows. An arbitrary measurement area of 3 fJ.ffi square (length: 3 J..llll,
width 3 J..llll) or 10 fJ.ffi square (length: 10 fJ.ffi, width 10 J..llll) of a diffraction grating is
measured by using an atomic force microscope to obtain a concavity-convexity analysis
image. The flat processing including the primary inclination correction is applied to the
obtained concavity-convexity analysis image, and then the two-dimensional high speed
Fourier transform processing is applied. Thus, a Fourier transform image is obtained.
The distance (unit: J.Uil-1
) from the origin of the Fourier transform image and the
intensity are determined for each point of the Fourier transform image. Subsequently,
the average value of intensities is obtained for the points positioned at an identical
distance. The relationship between the distance from the origin of the Fourier transform
image and the average value of intensities determined as described above is plotted.
The fitting is effected by using a spline function. The wave number, at which the
intensity provides the peak, is regarded as the average wave number (J..llll-1
), and the
38
reciprocal thereof is obtained to be regarded as the average pitch. Alternatively, it is
also allowable that the average pitch is obtained in accordance with another method.
For example, an arbitrary measurement area of 3 JllD. square (length: 3 J..LID., width 3 J..LID.)
or 10 JllD. square (length: 10 J..LID., width 10 J..LID.) of a diffraction grating is measured to
obtain a concavity-convexity analysis image. Not less than 100 spacing distances are
measured between arbitrary adjoining convexities or between arbitrary adjoining
concavities in the concavity-convexity analysis image, and an average thereof is
calculated to determine the average pitch of the concavity and convexity.
[0093] The Fourier transform image provides a circular motif or marking (pattern)
formed approximately about the center of the origin for which the absolute value of the
wave number is 0 J..LID.-1
• Further, the circular motif exists in the region (area) in which
the absolute value of the wave number is not more than 10 J..LID.-1 (more preferably in a
range of 0.667 J..LID.-1 to 10 J..LID.-1 and much more preferably in a range of 0.833 J..LID.-1 to 5
J..LID.-1
). The circular motif of the Fourier transform image is the motif observed by
assembling or gathering the bright spots in the Fourier transform image. The term
"circular" referred to herein means the fact that the motif obtained by assembling or
gathering the bright spots seems to have an approximately circular shape, which is the
concept including those in which a part of the outer shape is convex or concave as well.
The motif obtained by assembling or gathering the bright spots seems to be
approximately annular in some cases. In this case, the shape is expressed as "annular
shape". Note that the "annular shape" resides in the concept which includes those in
which the shapes of the outer circle and the inner circle of the ring seem to have
approximately circular shapes and which also includes those in which parts of the outer
shapes of the outer circle and the inner circle of the ring as described above seem to be
convex or concave. Further, the phrase "circular or annular motif exists in the region
(area) in which the absolute value of the wave number is not more than 10 J..LID.-1 (more
preferably in a range of 0.667 J..Un-1 to 10 J..Un-1 and much more preferably in a range of
0.833 J..Un-1 to 5 J..Un-1
)" refers to the fact that the bright spots of not less than 30% (more
preferably not less than 50%, much more preferably not less than 80%, and especially
preferably not less than 90%) of the bright spots for constructing the Fourier transform
image exist in the region (area) in which the absolute value of the wave number is not
more than 10 J..Un-1 (more preferably in a range of0.667 J..Un-1 to 10 J..Un-1 and much more
39
preferably in a range of 0.833 J.LID.-1 to 5 J..LID.-1
). Note that the following fact has been
revealed about the relationship between the pattern of the concave-convex structure and
the Fourier transform image. When the concave-convex structure itself has neither the
pitch distribution nor the directivity, the Fourier transform image also appears as a
random pattern (having no motif). However, when the concave-convex structure is
isotropic as a whole in the XY directions but the pitch involves the distribution, then a
circular or annular Fourier transform image appears. When the concave-convex
structure has the single pitch, there is such a tendency that the annular ring, which
appears on the Fourier transform image, becomes sharp.
[0094) The two-dimensional high speed Fourier transform process for the concavityconvexity
analysis image can be performed with ease by means of the electronic image
processing by using a computer provided with software of the two-dimensional high
speed Fourier transform process.
[0095) The average height (depth) of the concavities and convexities to represent the
mountain-like structure 38 or the wave-like structure 38a is preferably in a range of20
nm to 200 nm and more preferably in a range of 30 nm to 150 nm. If the average heigh :
of the concavities and convexities is less than the lower limit, then the height is
insufficient with respect to the wavelength of the visible light, and hence the diffraction
becomes insufficient. If the average height of the concavities and convexities exceeds
the upper limit, the electric field distribution in an EL layer becomes nonuniform when
the obtained diffraction grating is utilized as an optical element disposed on the light
extraction port side of an organic EL element. The element is easily destroyed by the
heat generated by the concentration of the electric field on the specified portion, and the
service life tends to become short. Note that the average height of the concavity and
convexity refers to the average value of the depth distribution of the concavity and
convexity when the height of the concavity and convexity (distance in the depth
direction between the concavity and the convexity) is measured on the surface of the
mountain-like structure 38 or the wave-like structure 38a. Further, the following value
is adopted for the average value of the depth distribution of the concavity and convexity
as described above. That is, the value is calculated such that the concavity-convexity
analysis image is measured by using a scanning probe microscope (for example, product
name: "E-sweep" produced by Sll Nanotechnology Inc.) in relation to the shape of the
40
I
concavity and convexity of the surface, and then not less than 100 distances in the depth
direction, each of which is provided between an arbitrary concavity and an arbitrary
convexity, are measured in the concavity-convexity analysis image as described above
so that an average thereof is determined.
[Seed layer forming step and electroforming step]
[0096] As shown in' Fig. 8A, a seed layer 40, which functions as an electroconductive
layer for a subsequent electroforming process, is formed on the surface of mountain-like
structure 38 of the master ootained in the second heating step as described above or the
wave-like structure 38a obtained in the solvent annealing step. The seed layer 40 can be
formed by the non-electrolytic plating, sputtering, or vapor deposition. The thickness of
the seed layer 40 is preferably not less than 10 nm and more preferably not less than 20
nm in order to uniformize the current density during the subsequent electroforming
process so that the thickness of the metal layer accumulated by the subsequent
electroforming process is made constant. As the material of the seed layer, it is possible
to use, for example, nickel, copper, gold, silver, platinum, titanium, cobalt, tin, zinc,
chromium, gold-cobalt alloy, gold-nickel alloy, boron-nickel alloy, solder, coppernickel-
chromium alloy, tin-nickel alloy, nickel-palladium alloy, nickel-cobaltphosphorus
alloy, or alloy thereof. Note that the seed layer is considered to adhere with
a uniform thickness without any leakage owing to the mountain-like or wave-like
relatively smooth structure as shown in Fig. 6D or Figs. 7 A and 7B as compared with
the complicated cross-sectional structure as shown in Fig. 6C.
[0097] Subsequently, a metal layer 50 is accumulated on the seed layer 40 by means of
the electro forming (electroplating), as shown in Fig. 8B. The whole thickness of the
metal layer 50 including the thickness of the seed layer 40 can be, for example, in a
range of 10 J..LID. to 3,000 J..LID.. As the material of the metal layer 50 to be accumulated by
the electro forming, it is possible to use any of metal species as described above which
can be used as the seed layer 40. Nickel is preferred in view of the wear resistance and
the releasing (exfoliation or peeling off) property as the mold of the metal substrate. In
this case, nickel is also preferably used for the seed layer 40. The current density during
the electroforrning may be, for example, in a range of 0.03 A/cm2 to 10 A/cm2 for
suppressing bridge to form a uniform metal layer and in view of shortening of
electroforming time (duration of electroforming time). Considering the easiness for
41
performing the subsequent processes such as pressing with respect to a resin layer,
releasing (exfoliation or peeling off), and cleaning (washing), the formed metal layer 50
desirably has appropriate hardness and thickness. A diamond like carbon (DLC)
processing or a Cr plating processing treatment may be carried out on the surface of the
metal layer in order to improve the hardness of the metal layer formed by the
electroforming. Alternatively, the surface hardness of the metal layer may be improved
or raised by further performing the heating process of the metal layer.
[Releasl.ng (exfoliation or peeling off) step]
[0098] The metal layer 50 including the seed layer 40 obtained as described above is
released (exfoliated or peeled off) from the base member having the concave-convex
structure to thereby obtain a metal substrate to serve as a father (father die). As the
releasing method (exfoliating or peeling method), the metal layer 50 may be released or
exfoliated physically, or the frrst homopolymer and the remaining block copolymer may
be dissolved and removed by using an organic solvent which dissolves the first
homopolymer and the remaining block copolymer, such as toluene, tetrahydrofuran
(THF), and chloroform.
[Cleaning (washing) step]
[0099] In a case of releasing the metal substrate 70 from the base member 10 having the
mountain-like structure 38 or the wave-like structure 38a as described abo~e. a polymer
portion or portions 60 of the polymer such as the first polymer segment and/or the
second polymer segment remain(s) on the metal substrate 70 in some cases, as shown in
Fig. 8C. In such a case, the remaining portion or portions 60 can be removed by
cleaning (washing). As a cleaning method, the wet cleaning or the dry cleaning can be
used. As for the wet cleaning, the remaining portion or portions 60 can be removed by
performing, for example, the cleaning with an organic solvent such as toluene and
tetrahydrofuran, a surfactant, or an alkaline solution. In a case that the organic solvent is
used, ultrasonic cleaning may be carried out. Alternatively, the remaining portion or
portions 60 may be removed by performing the electrolytic cleaning. As for the dry
cleaning, the remaining portion or portions 60 can be removed by means of the ashing
by using ultraviolet light and/or plasma. The wet cleaning and the dry cleaning may be
used in combination. After the cleaning as described above, a rinse process may be
performed with pure water or purified water, and then ozone irradiation may be carried
42
out after being dried. Thus, a metal substrate (mold) 70 having a desired concaveconvex
structure is obtained (Fig. 80). The metal substrate 70 is provided as the light
non-transmissive substrate which is the inspection objective for the inspection apparatus
and the inspection method of the present invention.
[0100] Next, a method for producing a diffraction grating usable for the organic EL
element, etc., by using the obtained metal substrate 70 will be explained with reference
to Figs. 9A to 9E.
[Mold-release treatment step for metal substrate]
[0101] In a case that the metal substrate 70 as the mold is used to transfer the concaveconvex
structure thereof to a resin, a mold-release treatment may be performed for the
metal substrate 70 in order to improve the releasability from the resin. As for the moldrelease
treatment, a manner or procedure to decrease the surface energy is generally
used. Although the mold-release treatment is not particularly limited, the mold-release
treatment includes, for example, a method in which a concave-convex surface 70a of the
metal substrate 70 is coated with a mold-release agent 72 such as a fluorine-based
material and a silicone resin, as shown in Fig. 9A, a method in which the surface is
subjected to a treatment by using a fluorine-based silane coupling agent, a method in
which a f:tlm of diamond like carbon is formed on the surface, etc.
[Transfer step to resin layer of metal substrate]
[0102] A master (mother) is produced by transferring the concave-convex structure
(pattern) of the metal substrate to a resin layer 80 by using the obtained metal substrate
70. As the method of the transfer process, for example, a transparent supporting
substrate 90 is coated with a curable resin, and then the resin layer 80 is cured while
pressing the concave-convex structure of the metal substrate 70 against the resin layer
80, as shown in Fig. 9B. Examples of the transparent supporting substrate 90 include a
base member composed of a transparent inorganic material such as glass; a base
member composed of a resin such as polyethylene terephthalate (PET), polyethylene
terenaphthalate (PEN), polycarbonate (PC), cycloolefin polymer (COP), polymethyl
methacrylate (PMMA) or polystyrene (PS); a stacked base member having a gas barrier
layer composed of an inorganic substance such as SiN, SiOz, SiC, SiOxNy, Ti02, or
Alz03 formed on the surface of a base member composed of any one of the foregoing
resins; and a stacked base member formed by alternately stacking a base member
43
composed of any one of the foregoing resins and a gas barrier layer composed of any
one of the foregoing inorganic substances. Further, the thickness of the transparent
supporting substrate may be in a range of 1 Jliil to 500 Jl.IIl.
[0103] The curable resin can be exemplified, for example, by resins such as
photocurable resins, thermosetting resins, moisture curing type resins, and chemical
curing type resins (two-liquid mixing type resins). Specifically, the curable resin can be
exemplified, for example, by various resins including, for example, monomers,
oligomers, and polymers of those based on epoxy, acrylic, methacrylic, vinyl ether,
oxetane, urethane, melamine, urea, polyester, polyolefm, phenol, cross-linking type
liquid crystal, fluorine, silicone, and polyamide. The thickness of the curable resin is
preferably in a range of 0.5 Jliil to 500 JliD. In a case that the thickness is less than the
lower limit, heights of the concavities and convexities formed on the surface of the
cured resin layer are more likely to be insufficient. In a case that the thickness exceeds
the upper limit, the influence of volume change of the resin which occurs upon curing is
likely to be so large that the formation of the shape of the concavities and convexities
tends to be unsatisfactory.
[0104] As a method for coating the transparent supporting substrate 90 with the curable
resin, for example, it is possible to adopt various coating methods such as the spin
coating method, spray coating method, dip coating method, dropping method, gravure
printing method, screen printing method, relief printing method, die coating method,
curtain coating method, ink-jet method, and sputtering method. Further, the condition
for curing the curable resin varies depending on the kind of the resin to be used.
However, for example, the curing temperature is preferably in a range of room
temperature to 250°C, and the curing time is preferably in a range of 0.5 minute to 3
hours. Alternatively, a method may be employed in which the curable resin is cured by
being irradiated with energy ray such as ultraviolet light or electron beam. In such a
case, the amount of the irradiation is preferably in a range of 20 mJ/cm2 to 5 J/cm2
•
[0105] Subsequently, the metal substrate 70 is detached from the curable rein layer 80
after the curing. The method for detaching the metal substrate 70 is not limited to a
mechanical releasing (exfoliating or peeling off) method, and any known arbitrary
method can be adopted. Then, as shown in Fig. 9C, it is possible to obtain a resin film
structure 100 having the cured rein layer 80 in which the concavities and convexities are
44
formed on the transparent supporting substrate 90. The resin film structure 100 may be
used, as it is, as the diffraction grating. The resin film structure 100 is the inspection
objective for the inspection apparatus and the inspection method of the present
invention, as provided as the light transmissive substrate.
[0106] The substrate production method based on the BCP method can be used not only
for producing a diffraction grating provided on the light extraction port side of the
organic EL element but also for producing an optical component having a minute or fme
pattern usable for various devices. For example, the substrate production method based
on the BCP method can be used to produce a wire grid polarizer, an antireflection film,
or an optical element for providing the light confmement effect in a solar cell by being
placed or installed on the photoelectric conversion surface side of the solar cell.
[0107] Thus, the resin film structure 100 having a desired pattern can be obtained.
When the inverted pattern of the resin film structure 100 is used as the diffraction
grating, then the resin film structure 100 obtained by performing the transfer process for
the metal substrate as described above is used as the master (mother), another
transparent supporting substrate 92 is coated with a curable resin layer 82, and the resin
film structure 100 is pressed against the curable resin layer 82 to cure the curable resin
layer 82, as shown in Fig. 9D, in the same manner as a case in which the resin film
structure 100 is manufactured. _Subsequently, the resin film structure 100 is released
(exfoliated or peeled off) from the curable resin layer 82 which has been cured, and thus
a replica 110 as another resin fllm structure as shown in Fig. 9E can be obtained.
Further, it is allowable to produce a replica having the inverted pattern of the replica 110
by carrying out the transfer step described above by using the replica 110 as a master
block, and/or it is allowable to form a sub-replica by repeating the transfer step
described above again by using the replica having the inverted pattern as the master
block. The replica 110 and the sub-replica as described above also have the irregular
concave-convex patterns on the surfaces, and hence they are the inspection objective for
the inspection apparatus and the inspection method of the present invention.
[0108] Next, an explanation will be made about a method for manufacturing or
preparing a structure having concavities and convexities composed of a sol-gel material
(hereinafter referred to as "sol-gel structure" or "sol-gel material substrate" as
appropriate) by further using the obtained resin fllm structure 100 as the master block.
45
A substrate-forming method for forming a substrate having a concave-convex pattern by
using the sol-gel material mainly includes: a solution preparation step for preparing a sol
solution; a coating step (application step) for applying the prepared sol solution onto a
substrate (coating the substrate with the prepared sol solution); a drying step for drying a
coating film of the sol solution with which the substrate is coated; a pressing step for
pressing a mold having a transfer pattern formed thereon; a pre-baking (pre-calcination)
step for subjecting the coating film pressed with the mold to the pre-baking, a releasing
(exfoliation or peeling off) step for releasing (exfoliating or peeling off) the mold from
the coating fllm; and a main baking (main calcination) step for subjecting the coating
fllm to main baking. In the following, each of the steps will be explained sequentially.
[0109] At first, a sol solution is prepared to form a coating fllm to which a pattern is to
be transferred by means of the sol-gel method (solution preparation step). For example,
in a case that silica is synthesized by means of the sol-gel method on the substrate, a sol
solution of metal alkoxide (silica precursor) is prepared. The silica precursor is
exemplified by metal alkoxides including, for example, tetraalkoxide monomers such as
tetramethoxysilane (TMOSS), tetraethoxysilane (TEOS), tetra-i-propoxysilane, tetra-npropoxysilane,
tetra-i-butoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and
tetra-t-butoxysilane; trialkoxide monomers such as methyltrimethoxysilane,
ethyltrimethoxys~ane, propyltrimethoxysilane, isopropyltrimethoxysilane,
phenyltrimethoxysilane, methyltriethoxysilane (MTES), ethyltriethoxysilane,
propyltriethoxysilane, isopropyltriethoxysilane, phenyltriethoxysilane,
methyltripropoxysilane, ethyltripropoxysilane, propyltripropoxysilane,
isopropyltripropoxysilane, phenyltripropoxysilane, methyltriisopropoxysilane,
ethyltriisopropoxysilane, propyltriisopropoxysilane, isopropyltriisopropoxysilane,
phenyltriisopropoxysilane, and tolyltriethoxysilane; dialkoxide monomers represented
by dialkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane,
dimethyldipropoxysilane, dimethyldiisopropoxysilane, dimethyl-di-n-butoxysilane,
dimethyl-di-i-butoxysilane, dimethyl-di-sec-butoxysilane, dimethyl-di-t-butoxysilane,
diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane,
diethyldiisopropoxysilane, diethyl-di-n-butoxysilane, diethyl-di-i-butoxysilane, diethyldi-
sec-butoxysilane, diethyl-di-t-butoxysilane, dipropyldimethoxysilane,
dipropyldiethoxysilane, dipropyldipropoxysilane, dipropyldiisopropoxysilane, dipropyl-
46
di-n-butoxysilane, dipropyl-di-i-butoxysilane, dipropyl-di-sec-butoxysilane, dipropyl-dit
-butoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane,
diisopropyldipropoxysilane, diisopropyldiisopropoxysilane, diisopropyl-di-nbutoxysilane,
diisopropyl-di-i-butoxysilane, diisopropyl-di-sec-butoxysilane,
diisopropyl-di-t-butoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane,
diphenyldipropoxysilane, diphenyldiisopropoxysilane, diphenyl-di-n-butoxysilane,
diphenyl-di-i-butoxysilane, diphenyl-di-sec-butoxysilane, and diphenyl-di-tbutoxysilane;
monomers having vinyl group such as vinyltrimethoxysilane and
vinyltriethoxysilane; monomers having epoxy group such as 2-(3,4-
epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-
glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-
glycidoxypropyltriethoxysilane; monomers having styryl group such as pstyryltrimethoxysilane;
monomers having methacrylic group such as 3-
methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-
methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane;
monomers having acrylic group such as 3-acryloxypropyltrimethoxysilane; monomers
having amino group such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane,
N-2-( aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-
_aminopropyltriethoxysilane, 3-triethoxysilyl-N-( 1 ,3-dimethyl-butylidene )propylamine,
. and N-phenyl-3-aminopropyltrimethoxysilane; monomer having ureide group such as 3-
ureidepropyltriethoxysilane; monomers having mercapto group such as 3-
mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane;
monomers having sulfide group such as bis(triethoxysilylpropyl) tetrasulfide; monomers
having isocyanate group such as 3-isocyanatopropyltriethoxysilane; polymers obtained
by polymerizing the foregoing monomers in small amounts; and composite materials
characterized in that functional group and/or polymer is/are introduced into a part of the
material as described above. Further, a part of or all of the alkyl group and the phenyl
group may be substituted with fluorine. Further, examples of the silica precurs,or
include metal acetylacetonate, metal carboxylate, oxychloride, chloride, and mixtures
thereof. The silica precursor, however, is not limited thereto. In addition to Si,
examples of the metal species include Ti, Sn, Al, Zn, 'h, In, and mixtures thereof, but
are not limited thereto. It is also possible to use any appropriate mixture of precursors
47
of the oxides of the foregoing metals. Further, a hydrophobization treatment may be
performed on the surface thereof. Any known method may be used as a method for the
hydrophobization treatment. For example, in the case of the silica surface, the
hydrophobization treatment can be performed, for example, with dimethyldichlorosilane
or trimethylalkoxysilane. It is also allowable to use a method in which the
hydrophobization treatment is performed with silicone oil and trimethylsilylating agent
such as hexamethyldisilazane. It is also allowable to use a surface treatment method for
metal oxide powder based on the use of supercritical carbon dioxide. Further, it is
possible to use, as the silica precursor, a silane coupling agent having, in its molecule, a
hydrolysis group having the afftnity and the reactivity with silica and an organic
functional group having the water-repellence. For example, there are exemplified silane
monomer such as n-octyltriethoxysilane, methyltriethoxysilane, and
methyltrimethoxysilane; vinylsilane such as vinlytriethoxysilane, vinyltrimethoxysilane,
vinyltris(2-methoxyethoxy)silane, and vinylmethyldimethoxysilane; methacrylsilane
such as 3-methacryloxypropyltriethoxysilane, and 3-
methacryloxypropyltrimethoxysilane; epoxysilane such as 2-(3,4-
epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-
glycidoxypropyltriethoxysilane; mercaptosilane such as 3-
mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; sulfursilane such
as 3-octanoylthio-1-propyltriethoxysilane; aminosilane such as 3-
aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-
aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,
and 3-(N-phenyl)-aminopropyltrimethoxysilane; and polymers obtained by polymerizing
the monomers as described ~bove.
[0110] In a case that a mixture ofTEOS and MTES is used, the mixture ratio thereof
can be 1: 1, for example, in a molar ratio. This sol solution produces amorphous silica
by performing the hydrolysis and the polycondensation reaction. An acid such as
hydrochloric acid or an alkali such as ammonia is added in order to adjust the pH of the
solution as a synthesis condition. The pH is preferably not more than 4 or not less than
10. Further, water may be added in order to perform the hydrolysis. The amount of
water to be added can be not less than 1.5 times that of metal alkoxide species, in the
molar ratio. As for the sol-gel material, it is possible to use a material other than silica.
48
For example, a material such as a Ti-based material, ITO (indium-tin oxide)-based
material, Ah03, Zr02, ZnO, etc., may be used.
[0111] Examples of the solvent include alcohols such as methanol, ethanol, isopropyl
alcohol (1P A), and butanol; aliphatic hydrocarbons such as hexane, heptane, octane,
decane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, and
mesitylene; ethers such as diethyl ether, tetrahydrofuran, and dioxane; ketones such as
acetone, methyl ethyl ketone, isophorone, and cyclohexanone; ether alcohols such as
butoxyethyl ether, hexyloxyethyl alcohol, methoxy-2-propanol, and benzyloxyethanol;
glycols such as ethylene glycol and propylene glycol; glycol ethers such as ethylene
glycol dimethyl ether, diethylene glycol dimethyl ether, and propylene glycol
monomethyl ether acetate; esters such as ethyl acetate, ethyl lactate, and "(butyrolactone;
phenols such as phenol and chlorophenol; amides such as N,Ndimethylformamide,
N,N-dimethylacetamide, and N-methylpyrrolidone; halogen-based
solvents such as chloroform, methylene chloride, tetrachloroethane,
monochlorobenzene, and dichlorobenzene; hetero element-containing compounds such
as carbon disulfide; water; and mixture solvents thereof. Especially, ethanol and
isopropyl alcohol are preferred, and it is also preferable to use those obtained by mixing
them with water.
[0112] As an additive, it is possible to use, for example, polyethylene glycol,
polyethylene oxide, hydroxypropylcellulose, and polyvinyl alcohol for viscosity
adjustment; alkanolamine such as triethanolamine, ~-diketone such as acetylacetone, ~ketoester,
formamid, dimetylformamide, and dioxane as a solution stabilizer.
[0113] The substrate is coated with the sol solution prepared as described above
(coating step). It is allowable to use, as the substrate, substrates made of inorganic
materials such as glass, silica glass, and silicon substrates, or substrates made of resins
such as polyethylene terephthalate (PET), polyethylene terenaphthalate (PEN),
polycarbonate (PC), cycloolefm polymer (COP), polymethyl methacrylate (PMMA),
polystyrene (PS), polyimide (PD. and polyarylate. The substrate may be either
transparent or opaque. In a case that a concave-convex patterned substrate obtained by
using this substrate is to be used for producing an organic EL element as described later
on, this substrate preferably is a substrate having the heat resistance and the light
resistance against the UV light, etc. In view of this fact, the substrates composed of the
49
inorganic materials such as the glass, silica glass and silicon substrates are more
preferred. It is allowable to perform a surface treatment or provide an easy-adhesion
layer on the substrate in order to improve the adhesion property, and it is allowable to
provide a gas barrier layer in order to keep out moisture and/or gas such as oxygen. As
for the coating method, it is possible to use any arbitrary coating method including, for
example, the bar coating method, the spin coating method, the spray coating method, the
dip coating method, the die coating method, and the ink-jet method. However, in view
of the fact that the substrate having a relatively large areal size can be uniformly coated
with the sol solution, and the coating can be completed quickly before the sol solution
forms a gel, it is preferable to use the bar coating method, the die coating method, and
the spin coating method. Note that a desired concave-convex pattern is formed with the
sol-gel material layer in a subsequent or following step, and thus the surface of the
substrate (including the surface treatment or the easy-adhesion layer in case that the
surface treatment has been performed or the easy-adhesion layer has been formed) may
be flat, while the substrate itself does not have the desired concave-convex pattern.
[0114] After the coating step, the substrate is kept (held) in the atmospheric air or under
reduced pressure in order to evaporate the solvent contained in the applied coating film
(hereinafter also referred to as "sol-gel material layer" as appropriate) (drying step).
Subsequently, the resin flim structure 100 (mold) is pressed against the coating flim
(pressing step). In this procedure, it is also allowable that the resin film structure 100 is
pressed by using a pressing roll. In the roll process, the following advantages are
obtained as compared with the press system. That is, the period of time during which
the mold and the coating film are brought in contact with each other is short, and hence
it is possible to prevent any deformation or collapse of pattern which would be
otherwise caused by the difference in coefficient of thermal expansion among the mold,
the substrate, and a stage in which the substrate is placed, etc. It is possible to prevent
the generation of bubbles of gas in the pattern which would be otherwise caused by the
bumping of the solvent in the gel solution and/or it is possible to prevent any trace or
mark of gas from remaining. It is possible to decrease the transfer pressure and the
releasing force (exfoliation or peeling force) owing to the line contact with the substrate
(coating film). It is easy to deal with those having larger areas (areal sizes). No bubble
is caught and included during the pressing. Further, it is also allowable to perform the
50
heating while allowing the resin film structure 100 to be pressed.
[0115] After the resin film structure 100 as the mold is pressed against the coating film
(sol-gel material layer), the coating film may be subjected to the pre-baking (precalcination)
(pre-baking step). The pre-baking promotes the gelation of the coating film
to solidify the pattern, thereby making the pattern be less likely to be collapsed during
the releasing or exfoliation. In a case that the pre-baking is performed, the heating is
preferably performed at a temperature in a range of 40°C to 150°C in the atmospheric
air. It is not necessarily indispensable to perform the pre-baking.
[0116] The resin film structure 100 is released (exfoliated) from the coating film (solgel
material layer) after the pressing step or the pre-baking step. When the roll is used
during the pressing procedure, it is enough that the releasing (exfoliation) force is small
as compared with any plate-shaped mold. The mold can be easily released (exfoliated)
from the coating film without allowing the coating film to remain on the mold.
[0117] After the resin film structure 100 is peeled off (exfoliated) from the coating film
(sol-gel material layer) on the substrate, the coating film is subjected to the main baking
(main calcination) (main baking step). The hydroxyl group or the like contained in
silica (amorphous silica) for constructing the coating film is eliminated (subjected to the
leaving) by the main baking, and the coating film is further strengthened. The main
baking may be performed at a temperature in a range of 200°C to l200°C for a duration
of time about in a range of 5 minutes to 6 hours. In such a manner, the coating film is
cured, and a sol-gel structure (diffraction grating) provided with a concave-convex
pattern film which corresponds to the concave-convex pattern of the resin film structure
100 is obtained, namely a sol-gel structure (diffraction grating) in which the sol-gel
material layer having the irregular concave-convex pattern is directly formed on the flat
substrate is obtained. In this situation, silica as the sol-gel material layer is amorphous,
crystalline, or in a mixture state of the amorphous and the crystalline, depending on the
baking temperature and the baking time. The sol-gel structure obtained as described
above is also the inspection objective for the inspection apparatus and the inspection
method of the present invention.
[0118] In a case that the replica 110 (or sol-gel structure) is to be duplicated by using
the resin film structure 100, or in a case that still another replica (or sol-gel structure) is
to be duplicated by using the obtained replica 110 (or sol-gel structure), a film may be
51
stacked on the surface of the resin ftlm structure 100 or the replica 110 having the
concave-convex pattern formed thereon, by means of a gas phase method such as the
vapor deposition method or the sputtering method. By stacking the ftlm as described
above, in a case that transfer etc. is performed, for example, by coating the st¢"ace
thereof with the resin, the adhesion with respect to the resin (for example, a UV curable
resin) can be lowered so as to allow the master block to be peeled off more easily.
Examples of the vapor-deposited ftlm as described above include metals such as
aluminum, gold, silver, platinum, and nickel; and metal oxides such as aluminum oxide.
Further, the thickness of such a ftlm is preferably in a range of 5 run to 500 run. In a
case that the thickness is less than the lower limit, a uniform ftlm is difficult to be
obtained, and thus the effect of sufficiently lowering the adhesion is decreased. In a
case that the thickness exceeds the upper limit, the shape of the master block is more
likely to be blunt or dull (loosened). In a case that the cured resin layer of the resin ftlm
structure 100 or the replica 110 is composed of a UV curable resin, postcure may be
conducted as appropriate, for example, by performing the irradiation with ultraviolet
light again after the resin has been cured.
[0119] Furthermore, in the steps shown in Figs. 9B and 9D, the curable resins 80, 82 are
applied onto the transparent supporting substrates 90, 92 respectively. It is allowable,
however, to use a master block obtained by applying the curable resin directly ont~ the
surface of the metal substrate 70 which is the original master block or onto the su;Iface
of the cured resin layer 80, curing the applied curable resin, and detaching the curable
resin after being cured. Alternatively, instead of coating the surface of the master block
with the resin, it is allowable to press the master block against a coating film of the resin
so that the concave-convex film of the cured resin obtained by curing the resin is used as
the master block.
B. Method for producing substrate by BKL method
[0120] As described in W02011/007878Al in detail, the BKL method comprises a step
(concave-convex shape forming step) for forming concavities and convexities based on
wrinkles on a surface of a vapor deposition film by forming the vapor deposition film on
a surface of a polymer film composed of a polymer having the volume which changes
depending on the heat under a temperature condition of not less than 70°C and then
cooling the polymer film and the vapor deposition film, and a step (master block
52
forming step) for adhering and curing a master block material on the vapor deposition
film and then detaching the master block material after the curing from the vapor
deposition film to obtain a master block.
[0121] Figs. lOA to lOD show schematic views for illustrating a preferred embodiment
of the method for producing the master block in the method for producing the
diffraction grating in accordance with the BKL method. Fig. lOA shows a sectional
view schematically illustrating a state in which a vapor deposition film 28 is formed on
a surface of a polymer film 27 in the method for producing the master block. Fig. lOB
shows a sectional view schematically illustrating a state in which concavities and
convexities based on wrinkles are formed on a surface of the vapor deposition film 28
by cooling the polymer film 27 and the vapor deposition film 28. Fig. lOC shows a
sectional view schematically illustrating a state in which a master block material 29 is
adhered and cured on the vapor deposition film 28 formed with the concavities and
convexities. Fig. lOD shows a sectional view schematically illustrating a state in which
the master block 29 after the curing is detached from the vapor deposition film 28.
[0122] In the concave-convex shape forming step, at first, the polymer film composed
of a polymer having the volume which is changed depending on the heat is prepared.
As for the polymer in which the volume is changed depending on the heat, it is possible
to appropriately use those in which the volume is changed by me~s of the heating or
the cooling (for example, those having the coefficient of thermal e~tpansion of not less
than 50 ppm/K). However, in view of the fact that the concavities and convexities are
easily formed by the wrinkles on the surface of the vapor deposition film because the
difference is large between the coefficient of thermal expansion of the polymer and the
coefficient of thermal expansion of the vapor deposition film and the high flexibility is
provided, it is more preferable to use silicone-based polymer, and it is especially
preferable to use silicone-based polymer containing polydimethylsiloxane. As for the
method for forming the polymer film as described above, it is possible to adopt, for
example, the spin coating method, dip coating method, dropping method, gravure
printing method, screen printing method, relief printing method, die coating method,
curtain coating method, ink-jet method, spray coating method, sputtering method,
vacuum vapor deposition method, etc. Further, the thickness of the polymer film as
described above is preferably in a range of 10 J..Lm to 5,000 J..Ull and more preferably in a
53
range of 10 J.1IIl to 2,000 Jllll.
[0123] Subsequently, in the concave-convex shape forming step, the vapor deposition
film 28 is formed on the surface of the polymer film 27 under the temperature condition
of not less than 70°C (see Fig. lOA). It is necessary that the temperature, which is
adopted when the vapor deposition film 28 is formed, should be not less than 70°C.
However, it is more preferable that the temperature is not less than 90°C. If the
temperature is less than 70°C, it is impossible to sufficiently form the concavities and
convexities based on the wrinkles on the surface of the vapor deposition film. As for
the method for forming the vapor deposition film 28, it is possible to appropriately
adopt any known method include, for example, the vapor deposition method and the
sputtering method. Among the method as described above, it is preferable to adopt the
vapor deposition method in view of the fact that the shapes of the concavities and
convexities formed on the surface of the polymer film are maintained. Further, the
material of the vapor deposition film 28 is not specifically limited. However, the
material is exemplified, for example, by metals such as aluminum, gold, silver,
platinum, and nickel; and metal oxides such as aluminum oxide.
[0124] Subsequently, in the concave-convex shape forming step, the polymer film 27
and the vapor deposition film 28 are cooled, and th':JS the concavities and convexities
based on the wrinkles are formed on the surface of the vapor deposition film 28 (see
Fig. lOB). As described above, there is a difference between the coefficient of thermal
expansion of the polymer film 27 and the coefficient of thermal expansion of the vapor
deposition film 28. Therefore, the polymer film 27 and the vapor deposition film 28 as
shown in Fig. lOA undergo the change of the volume caused by the heat respectively,
and it is possible to form the concavities and convexities based on the winkles (so-called
buckling pattern or so-called Turing pattern) on the surface of the vapor deposition film
28 as shown in Fig. lOB. Further, it is preferable that the temperatures of the polymer
film 27 and the vapor deposition film 28 after the cooling are not more than 40°C. If the
temperatures of the polymer film 27 and the vapor deposition film 28 after the cooling
exceed the upper limit, there is such a tendency that it is difficult to form the concavities
and convexities based on the winkles on the surface of the vapor deposition film.
Further, it is preferable that the temperature decreasing velocity (temperature lowering
velocity), which is adopted when the polymer film 27 and the vapor deposition film 28
54
are cooled, is in a range of 1 °C/minute to 80°C/minute. If the temperature decreasing
velocity is less than the lower limit, there is such a tendency that the concavities and
convexities are mitigated. On the other hand, if the temperature decreasing velocity
exceeds the upper limit, there is such a tendency that scratches such as cracks or the like
are easily formed on the surface of the polymer film or the vapor depasition film.
[0125] In the master block forming step, at frrst, as shown in Fig. lOC, a master block
material 29 is adhered and cured on the vapor deposition film 28. The master block
material 29 as described above is not specifically limited. The master block material 29
is exemplified, for example, by inorganic substances such as nickel, silicon, silicon
carbide, tantalum, glassy carbon, silica glass, and silica; and resin compositions such as
silicone-based polymer (silicone rubber), urethane rubber, norbomene resin,
polycarbonate, polyethylene terephthalate, polystyrene, polymethyl methacrylate,
acrylic, and liquid crystal polymer. Among the master block materials 29 as described
above, in view of the moldability, the fme shape following performance, and the mold
release, it is more preferable to use silicone-based polymer, nickel, silicon, silicon
carbide, tantalum, glassy carbon, silica glass, and silica, it is much more preferable to
use silicone-based polymer, and it is especially preferable to use silicone-based polymer
containing polymethylsiloxane. Further, the method for adhering the master block
material 29 as described above is not_ specifically limited. For example, it is possible to
adopt various coating methods including, for example, the vacuum vapor deposition
method, spin coating method, spray coating method, dip coating method, dropping
method, gravure printing method, screen printing method, relief printing method, die
coating method, curtain coating method, ink-jet method, and sputtering method.
Further, the condition, under which the master block material29 is cured, differs
depending on the kind or type of the master block material to be used. However, for
example, it is preferable that the curing temperature is in a range of room temperature to
250°C, and the curing time is in a range of 0.5 minute to 3 hours. Further, it is also
allowable to adopt a method in which the curing is performed by radiating the energy
ray such as ultraviolet light or electron beam. In such a case, it is preferable that the
amount of irradiation is in a range of 20 mJ/cm2 to 10 J/cm2
•
[0126] After that, in the master block forming step, as shown in Fig. lOD, the master
block material 29 after the curing is detached from the vapor deposition film 28 to
55
obtain the master block 29. The method for detaching the master block 29 from the
vapor deposition film 28 is not specifically limited. It is possible to appropriately adopt
any known method. The master block 29 obtained as described above is the inspection
objective for the inspection apparatus and the inspection method of the present
invention. Further, the substrate having the irregular concave-convex pattern on the
surface obtained in the middle of the process, for example, the substrate having the
buckling pattern as shown in Fig. lOB is also the inspection objective for the inspection
apparatus and the inspection method of the present invention.
[0127] In the BKL method, it is also allowable that the concave-convex shape forming
step and the master block forming step are repeated by using the master block 29
obtained as the polymer film. In this way, it is possible to deepen the wrinkles formed
on the surface of the master block, and it is possible to increase the average height of the
concavities and convexities formed on the surface of the master block.
[0128] Further, it is also allowable that a film, which is obtained by applying a resin
(material used for the master block material) to the surface of the obtained master block
29, curing the resin, and then detaching the cured resin, is used as a master block.
Furthermore, it is also allowable that a concave-convex film of curable resin, which is
obtained by pressing the master block 29 against a coating film of resin and curing the
resin in place of the application of the resin to the surface of the obtained master block
29, is used as a master block. As described above, a resin film, in which the concavities
and convexities are inverted, can be also utilized as a master block.
[0129] Further, it is also allowable that a fmal master block is produced by repeating the
inversion and the transfer of the concavities and convexities by the aid of one or more
intermediate master block or master blocks as starting from the master block 29. As for
the intermediate master block as described above, it is possible to utilize one obtained
by appropriately inverting or transferring the concave-convex structure as described
above. Furthermore, when the master block is produced by repeating the inversion and
the transfer of the concavities and convexities as described above, it is also possible to
once perform the transfer to a flexible material (for example, plastic film or silicone
rubber), in order that the transfer of the concave-convex structure is made easy even
when a substrate having no flexibility (for example, glass), with which it is difficult to
release (exfoliate or peel off) the resin film or the like, is used, when the concave-
56
convex structure of the master block is transferred. There is such a tendency that the
concave-convex structure is matched with the employed master block (parity is
adjusted) with ease. Moreover, it is also allowable that the intermediate master block as
described above is coated with a polymer in which the volume is changed by the heat, a
polymer fJ.lm obtained by the curing is used as a master-block 29, and the concaveconvex
shape forming step and the master block forming step are further repeated.
Moreover, it is also allowable that when the intermediate master block is composed of
UV -curable resin, then the ultraviolet light is radiated during the production to obtain an
intermediate master block, and the ultraviolet light is thereafter radiated again to
perform the postcure. In this way, when the master block composed of the UV -curable
resin is irradiated with the ultraviolet light again to perform the postcure, then there is
such a tendency that the degree of crosslinking of the master block is improved, and the
mechanical strength and the chemical resistance are improved.
[0130] Further, it is also allowable that the plating process is applied to the master block
(including the intermediate master block) by utilizing any known method to convert the
master block into a metal mold or die. When the master block is subjected to the plating
so that the master block is converted into the metal mold or die as described above,
there is such a tendency that the master block, which is excellent in the mechanical
strength and which is repeatedly usable, is obtained. When the master block subjected
to the plating as described above is used as a mold for the nano-imprinting or the like, it
is possible to mass-produce the resin substrate having a predetermined concave-convex
pattern by repeatedly performing the transfer to the curable resin substrate. Materials,
which can be used for the plating as described above, are exemplified, for example, by
nickel, copper, iron, nickel-cobalt alloy, and nickel-iron alloy. Note that the thickness
of the plating layer as described above is preferably 50 f..l.II1 to 1 mm, for example, in
view of the mechanical strength and the time required for manufacturing or preparing
the mold.
[0131] The master block (for example, the master block 29 and the master block
obtained by repeating the concave-convex shape forming step and the master block
forming step by using the master block 29 obtained as the polymer film), which is
obtained by carrying out the BKL method as described above, can be used as the master
block for forming the diffraction grating. Further, it is also allowable that a sol-gel
57
structure, which has concavities and convexities composed of a sol-gel material, is
manufactured by further using, as the master block, the resin substrate obtained by
carrying out the BKL method, in the same manner as the procedure in which the sol-gel
structure having the concavities and convexities composed of the sol-gel material is
manufactured by further using, as the master block, the resin ftlm structure obtained by
the BCP method.
[0132] Further, it is also allowable that a master block, which is obtained by heating the
master block obtained by the BKL method for about 1 hour to 48 hours under a
temperature condition of about 80°C to 200°C, is used as the master block to be used for
the production of the diffraction grating. When the master block is heated as described
above, a diffraction grating is obtained, especially a diffraction grating having the
concave-convex structure satisfactory for the organic EL element is obtained. The
substrate (master block}, which has the irregular concave-convex pattern on the surface,
is obtained by carrying out the BKL method as described above. Any substrate and any
sol-gel structure, which are obtained by the transfer by using the substrate as described
above, are also the inspection objective for the inspection apparatus and the inspection
method of the present invention.

[0133] Next, the organic EL element is produced by using the substrate which is judged
to be acceptable in the judging step described above and which is included in the resin
film structures (or the glass substrates or the sol-gel structures having the concavities
and convexities formed with the sol-gel material) obtained by using the method as
exemplified by the BCP method and the BKL method. In relation to the production
method, an explanation will be made with reference to Fig. 11 about the diffraction
grating composed of the resin film structure 100.
[0134] At first, as shown in Fig. 11, a transparent electrode 3 is stacked on the resin
layer 80 of the resin film structure 100 so as to maintain the concave-convex structure
formed on the surface of the resin layer 80. Examples of those usable as the material for
the transparent electrode 3 include indium oxide, zinc oxide, tin oxide, indium-tin oxide
(ITO) which is a composite material thereof; gold; platinum; silver; copper, etc. Among
these materials, ITO is preferred from the viewpoint of the transparency and the
electrical conductivity. The thickness of the transparent electrode 3 is preferably within
58
a range of 20 run to 500 run. In a case that the thickness is less than the lower limit, the
electrical conductivity is more likely to be insufficient. In a case that the thickness
exceeds the upper limit, there is possibility that the transparency is so insufficient that
the emitted EL light cannot be extracted to the outside sufficiently. As the method for
stacking the transparent electrode 3, it is possible to appropriately adopt any known
method such as the vapor deposition method and sputtering method, etc. Among these
methods, the sputtering method is preferably employed from the viewpoint of improving
adhesion property. Note that a glass substrate may be stuck to the side opposite to the
resin layer 80 of the resin film structure 100 before providing the transparent electrode 3
on the resin layer 80.
[0135] Subsequently, an organic layer 4 as shown in Fig. 11 is stacked on the
transparent electrode 3 so that the concave-convex shape formed on the surface of the
resin layer 80 is maintained. The organic layer 4 as described above is not particularly
limited, provided that the organic layer 4 is one usable as an organic layer of the organic
EL element. As the organic layer 4, any known organic layer can be used as
appropriate. Further, the organic layer 4 as described above may be a stacked body of
various organic thin films, and may be, for example, a stacked body composed of an
anode buffer layer 11, a hole (positive hole) transporting layer 12, and an electron
transporting layer 13 as shown in Fig. 11. In this context, the material for the anode
buffer layer 11 is exemplified, for example, by copper phthalocyanine and PEDOT.
Further, the material for the hole transporting layer 12 is exemplified, for example, by
triphenylamine, triphenyldiamine derivative (TPD), benzidine, pyrazoline, styrylamine,
hydrazone, triphenylmethane, carbazole, and derivatives thereof. Further, the material
for the electron transporting layer 13 is exemplified, for example, by aluminum
quinolinol complex (Alq), phenanthroline derivative, oxadiazole derivative, triazole
derivative, phenylquinoxaline derivative, and silole derivative. The organic layer 4 as
described above may be a stacked body of a hole injecting layer composed of, for
example, triphenylamine derivative and a light emitting layer composed of fluorescent
organic solid such as anthracene or the like, a stacked body of a light emitting layer as
described above and an electron injecting layer composed of perylene derivative or the
like, or a stacked body of a hole injecting layer, a light emitting layer, and an electron
injecting layer as described above.
59
[0136] The organic layer 4 may be a stacked body composed of a hole transporting
layer, a light emitting layer, and an electron transporting layer. In this case, examples of
the material of the hole transporting layer include aromatic diamine compounds such as
phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, N,N'bis(
3-methylphenyl)-(l,l '-biphenyl)-4,4'-diamine (TPD), and 4,4'-bis[N-(naphthyl)-Nphenyl-
amino]biphenyl (a.-NPD); oxazole; oxadiazole; triazole; imidazole;
imidazolone; stilbene derivatives; pyrazoline derivatives; tetrahydroimidazole;
polyarylalkane; butadiene; and 4,4',4"-tris(N-(3-methylphenyl)Nphenylamino)
triphenylamine (m-MTDATA). The material of the hole transporting
layer, however, is not limited thereto.
[0137] Further, the light emitting layer is provided so that a hole (positive hole) injected
from the transparent electrode and an electron injected from a metal electrode are
recombined to emit light. Examples of the material usable as the light emitting layer
include: metallo-organic complex such as anthracene, naphthalene, pyrene, tetracene,
coronene, perylene, phthaloperylene, naphthaloperylene, diphenylbutadiene,
tetraphenylbutadiene, coumarin, oxadiazole, bisbenzoxazoline, bisstyryl,
cyclopentadiene, and aluminum-quinolinol complex (Alq3); tri-(p-terphenyl-4-yl)amine;
1-aryl-2,5-di(2-thienyl) pyrrole derivatives; pyran; quinacridone; rubren;
distyrylbenzene derivatives; distyryl arylene derivatives; .distyryl amine derivatives; and
various fluorescent pigments or dyes. Furthermore, it is also preferable that lightemitting
materials selected from the foregoing compounds are mixed as appropriate and
then are used. Moreover, it is possible to preferably use a material system which
exhibits emission of light from a spin multiplet, such as a phosphorescence emitting
material which generates emission of phosphorescence, and a compound which
includes, in a part of the molecules, a constituent portion formed by the foregoing
materials as well. Note that the phosphorescence emitting material preferably includes
heavy metal such as iridium.
[0138] A host material having high carrier mobility may be doped with each of the
foregoing light-emitting materials as a guest material to cause the light emission by
utilizing the dipole-dipole interaction (Forster mechanism) or the electron exchange
interaction (Dexter mechanism). Examples of the material of the electron transporting
layer include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted
60
fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, and
naphthaleneperylene; and metallo-organic complex such as carbodiimide, fluorenylidene
methane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole
derivatives, and aluminum-quinolinol complex (Alq3). Further, in the oxadiazole
derivatives described above, it is also possible to use, as an electron transporting
material, thiadiazole derivatives in which oxygen atoms of oxadiazole rings are
substituted by sulfur atoms and quinoxaline derivatives having quinoxaline rings known
as electron attracting group (electron withdrawing group). Furthermore, it is also
possible to use a polymeric (macromolecular) material in which the material as
described above is introduced into a macromolecular chain or the material as described
above is used as a main chain of a macromolecule. Note that the hole transporting layer
or the electron transporting layer may also function as the light-emitting layer. In this
case, two organic layers are provided between the transparent electrode and the metal
electrode described later on.
[0139] Further, from the viewpoint of facilitating the electron injection or the hole
injection into the organic layer 4 as described above, a layer composed of a metal
fluoride such as lithium fluoride (LiF) or LhOJ, a highly active alkaline earth metal such
as Ca, Ba, or Cs, an organic insulating material or the like may be provided on the
transparent electrode 3 or the organic layer 4.
[0140] In a case that the organic layer 4 is a stacked body composed of the anode buffer
layer 11, the hole transporting layer 12, and the electron transporting layer 13, the
thicknesses of the anode buffer layer 11, the hole transporting layer 12, and the electron
transporting layer 13 are preferably in a range of 1 nm to 50 nm, a range of 5 nm to 200
nm, and a range of 5 nm to 200 nm respectively, in view of the fact that the shapes of
the concavities and convexities formed on the surface of the cured resin layer are
maintained. Further, in a case that the organic layer 4 is a stacked body composed of the
hole transporting layer, the light emitting layer, and the electron transporting layer, the
thicknesses of the hole transporting layer, the light emitting layer, and the electron
transporting layer are preferably in a range of 1 nm to 200 nm, a range of 5 nm to 100
nm, and a range of 5 nm to 200 nm respectively. As the method for stacking the organic
layer 4, any known method such as the vapor deposition method, sputtering method, and
die coating method can be employed as appropriate. Among the methods as described
61
above, it is preferable to use the vapor deposition method in view of the fact that the
shapes of the concavities and convexities formed on the surface of the resin layer 80 are
maintained.
[0141] In the step for forming the organic EL element, subsequently, as shown in Fig.
11, a metal electrode 5 is stacked on the organic layer 4 so that the shapes of the
concavities and convexities formed on the surface of the resin layer 80 are maintained.
Materials of the metal electrode 5 are not particularly limited, and a substance having a
small work function can be used as appropriate. Examples of the materials include
aluminum, MgAg, Mgln, and AlLi. The thickness of the metal electrode 5 is preferably
in a range of 50 nm to 500 nm. In a case that the thickness is less than the lower limit,
the electrical conductivity is more likely to be decreased. In a case that the thickness
exceeds the upper limit, there is possibility that it is difficult to maintain the concaveconvex
shape. Any known method such as the vapor deposition method, sputtering
method, etc. can be adopted to stack the metal electrode 5. Among the methods as
described above, it is preferable to use the vapor deposition method in view of the fact
that the concave-convex structure formed on the surface of the resin layer 80 is
maintained. Accordingly, an organic EL element 400 having a structure as shown in
Fig. 11 is obtained.
[0142] The resin layer 80 of the resin film structure 100 produced by the BCP method
has the mountain-like structure or the wave-like structure. Therefore, the transparent
electrode 3, the organic layer 4, and the metal electrode 5 are easily stacked respectively
so that the mountain-like or wave-like structure of the resist layer 80 is maintained. It is
possible to sufficiently suppress such a situation that the light, which is generated by the
organic layer 4, is totally reflected by the respective interfaces to repeat the multi path
reflection (multiple reflection) at the inside of the element. Further, the light, which has
been totally reflected by the interface between the transparent supporting substrate 90
and the air, can be allowed to outgo again in accordance with the diffraction effect.
Furthermore, the transparent electrode 3, the organic layer 4, and the metal electrode 5
also easily form the structures which are the same as or similar to the mountain-like or
wave-like structure formed on the surface of the resin layer 80. As a result, the distance
between the electrodes of the transparent electrode 3 and the metal electrode 5 is
partially shortened. Therefore, it is possible to expect the increase in the electric field
62
intensity during the application of the voltage as compared with those in which the
distance between the electrodes of the transparent electrode 3 and the metal electrode 5
is uniform. It is also possible to improve the light emission efficiency of the organic EL
element.
[0143] In the diffraction grating (substrate) produced according to the substrate
production method of the present invention and the organic EL element containing the
same, the average height of the concavities and convexi~es formed on the surface of the
diffraction grating (surface of the cured curable resin) is preferably in a range of 20 nm
to 200 nm and more preferably in a range of 30 nm to 150 nm as described above.

We claim:
1. A substrate inspection apparatus for inspecting a substrate having an
irregular concave-convex surface for scattering lights, comprising:
a first irradiation system which irradiates the substrate with a fust detection
light;
a first detection system which detects any luminance unevenness from the entire
concave-convex surface of the substrate irradiated with the first detection light;
a second irradiation system which irradiates the substrate with a second
detection light having a wavelength different from that of the first detection light; and
a second detection system which detects any defect of the concave-convex
surface of the substrate irradiated with the second detection light.
2. The substrate inspection apparatus according to claim 1, wherein the first
detection light is a blue light, and the second detection light is a white light.
3. The substrate inspection apparatus according to claim 1 or 2, wherein the
first irradiation system includes a transmitting light illumination for illuminating a light
transmissive substrate and a non-transmitting light illumination for illuminating a light
non-transmissive substrate, and the second irradiation system includes a transmitting
light illumination for illuminating the light transmissive substrate and a non-transmitting
light illumination for illuminating the light non-transmissive substrate.
4. The substrate inspection apparatus according to claim 3, wherein the
non-transmitting light illumination of the first irradiation system and the nontransmitting
light illumination of the second irradiation system irradiate the irregular
concave-convex surface of the substrate, and the transmitting light illumination of the
first irradiation system and the transmitting light illumination of the second irradiation
system irradiate the irregular concave-convex surface of the substrate from a surface
disposed on a side opposite to the irregular concave-convex surface of the substrate.
5. The substrate inspection apparatus according to claim 3 or 4, wherein the
81
first detection system includes a camera which detects the light coming from the light
transmissive substrate illuminated with the transmitting light illumination of the fust
irradiation system and the light coming from the light non-transmissive substrate
illuminated with the non-transmitting light illumination of the fust irradiation system.
6. The substrate inspection apparatus according to claim 5, wherein the
second detection system includes a camera which detects the light coming from the light
transmissive substrate illuminated with the transmitting light illumination of the second
irradiation system and the light coming from the light non-transmissive substrate
illuminated with the non-transmitting light illumination of the second irradiation system.
7. The substrate inspection apparatus according to claim 6, wherein a
resolution of the camera of the second detection system is higher than a resolution of the
camera of the first detection system.
8. The substrate inspection apparatus according to claim 6 or 7, wherein the
camera of the second detection system includes a plurality of cameras which detect
divided areas of the substrate respectively.
9. The substrate inspection apparatus according to any one of claims 1 to 8,
wherein the first irradiation system and the second irradiation system are line-shaped
illuminations extending in a predetermined direction, and the apparatus further
comprises a substrate transport system which transports the substrate in a direction
perpendicular to the predetermined direction.
10. The substrate inspection apparatus according to claim 9, further
comprising a control system which controls the substrate transport system, the first
irradiation system, the second irradiation system, the first detection system, and the
second detection system, wherein the control system detects the defect of the concaveconvex
surface when the substrate is moved by the substrate transport system in one
direction with respect to the first irradiation system, the second irradiation system, the
first detection system, and the second detection system, and the control system detects
82
the luminance unevenness when the substrate is moved in a direction opposite to the one
direction with respect to the first irradiation system, the second irradiation system, the
first detection system, and the second detection system.
11. The substrate inspection apparatus according to claim 10, wherein the
control system judges whether or not the defect of the concave-convex surface and the
luminance unevenness are within predetermined allowable ranges.
12. A substrate inspection method for inspecting a light non-transmissive
substrate having an irregular concave-convex surface for scattering lights and a light
transmissive substrate having an irregular concave-convex surface for scattering lights,
the substrate inspection method comprising:
transporting the substrate with respect to a first detection system which detects
any luminance unevenness from the entire concave-convex surface of the substrate and a
second irradiation system which detects any defect of the concave-convex surface of the
substrate;
irradiating the concave-convex surface of the substrate with a first detection light
to detect the light coming from the concave-convex surface by the first detection system,
and irradiating the concave-convex surface of the substrate with a second detection l~ght
having a wavelength different from that of the first detection light to detect the light
coming from the concave-convex surface by the second detection system, when the light
non-transmissive substrate is transported; and
irradiating the irregular concave-convex surface of the substrate with the first
detection light from a surface of the light transmissive substrate disposed on a side
opposite to the concave-convex surface to detect the light coming from the concaveconvex
surface by the first detection system, and irradiating the irregular concaveconvex
surface of the substrate with the second detection light from the surface of the
light transmissive substrate disposed on the opposite side to detect the light coming
from the concave-convex surface by the second detection system, when the light
transmissive substrate is transported.
13. The substrate inspection method according to claim 12, wherein the first
83
detection light is a blue light, and the second detection light is a white light.
14. The substrate inspection method according to claim 12 or 13, wherein
each of the first irradiation system and the second irradiation system is a line-shaped
illumination extending in a predetermined direction, and the transport of the substrate is
to transport the substrate in a direction perpendicular to the predetermined direction.
15. The substrate inspection method according to any one of claims 12 to 14,
wherein the defect of the concave-convex surface of the substrate is detected when the
substrate is moved in one direction with respect to the first detection system and the
second detection system, and the luminance unevenness of the substrate is detected
when the substrate is moved in a direction opposite to the one direction with respect to
the first detection system and the second detection system.
16. The substrate inspection method according to any one of claims 12 to 15,
further comprising judging whether or not the defect of the concave-convex surface and
the luminance unevenness are within predetermined allowable ranges.
17. A substrate production method for producing a substrate having an
irregular concave-convex surface for scattering lights, comprising:
preparing the substrate having the irregular concave-convex surface; and
inspecting the substrate having the irregular concave-convex surface by using the
substrate inspection method as defmed in any one of claims 12 to 16.
18. The substrate production method according to claim 17, wherein the
preparation of the substrate having the irregular concave-convex surface comprises
preparing a light non-transmissive substrate having an irregular concave-convex pattern,
and transferring the irregular concave-convex pattern of the light non-transmissive
substrate.
19. The substrate production method according to claim 17 or 18, wherein
the preparation of the substrate having the irregular concave-convex surface comprises
84
utilizing phase separation of a block copolymer.
20. The substrate production method according to any one of claims 17 to
19, wherein the irregular concave-convex surface is formed of a metal, resin, or sol-gel
material.
21. A method for producing an organic electroluminescent element,
comprising preparing a diffraction grating substrate having a concave-convex surface by
the substrate production method as defmed in any one of claims 17 to 20, and
successively stacking a transparent electrode, an organic layer, and a metal electrode on
the concave-convex surface of the diffraction grating substrate.
22. The method for producing the organic electroluminescent element
according to claim 21, wherein the substrate inspection method comprises judging
whether or not the defect of the concave-convex surface and the luminance unevenness
are within predetermined allowable ranges, and the transparent electrode, the organic
layer, and the metal electrode are successively stacked on the concave-convex surface of
the diffraction grating substrate only when it is judged that the luminance unevenness
and the defect of the prepared diffraction grating substrate are within the predetermined
allowable ranges.