• DESCRIPTION
SEMICONDUCTOR DEVICE PRODUCTION METHOD AND RINSE
Technical Field
[0001] The present invention relates to a semiconductor device production method, and a
nnse.
Background Art
[0002] In the field of semiconductor devices, with a trend of miniaturization, various
investigations have been made on materials with a low dielectric constant (hereinafter, also
referred to as "low-k materials") that have a porous structure, as an interlayer dielectric layer
of a semiconductor.
In a semiconductor interlayer dielectric layer having a porous structure, when the
void fraction thereof is increased in order to further lower the dielectric constant, a metal
component such as copper, which is embedded as a wiring material, may readily enter the fine
pores of the semiconductor interlayer dielectric layer, thereby increasing the dielectric
constant or generating a leak current.
[0003] On the other hand, in the semiconductor device production method by using a porous,
low dielectric constant material, a technique of sealing fine pores on side walls of grooves that
have been formed by etching, using a micelle-type surfactant in wet washing after the etching,
has been known (see, for example, Patent Document 1).
Further, when the low-k material has a hydrophobic surface, a technique of
controlling the hydrophilicity or hydrophobicity of the material by applying a polyvinyl
alcohol-based amphipathic polymer to its surface has been known (see, for example, Patent
Document 2). ~
Moreover, a composition for polishing a semiconductor, which includes a cationic
polymer and a surfactant, has been known (see, for example, Patent Ddcument 3).
[0004] In the me~hod for manufacturing a semiconductor device by using a porous, low
dielectric constant material, at the time of sealing fine pores on side walls or the like of
grooves that have been formed by etching, if there is a wiring line formed from copper or the
like on the surface of the substrate together with a porous interlayer dielectric layer, the
material used for sealing (sealing composition) may adhere to the wiring line. Such an extra
sealing composition needs to be removed, since it may cause circuit malfunction or corrosion
of a semiconductor device. As such, there has been a demand for a method (hereinafter, also
referred to ~s a "rinsing method") of rapidly removing the extra sealing composition on the
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wiring line, while leaving the material that seals the fine pores, and a rinse (hereinafter, also
referred to as a "cleaning agent").
[0005] Further, an extra material that does not form a constituent element of a
semiconductor circuit, which exists on the peripheral area of the surface of a semiconductor
substrate on which a circuit is not formed or at the back face of the semiconductor substrate
on which the dielectric film is not formed, and the like, may exfoliate during the process of
manufacturing the semiconductor, and may contaminate the semiconductor substrate.
Therefore, the extra material needs to be removed by a method such as back rinsing or edge
rinsing. Accordingly, there has been a demand for a method of rapidly removing the film
that is formed on a semiconductor device.
[0006]
[Patent Document 1] Japanese National Phase Publication No. 2009-503879
[Patent Document 2] WO 09/012184, Pamphlet
[Patent Document3] Japanese Patent Application Laid-Open (JP-A) No..2006-352042
DISCLOSURE OF INVENTION
Technical Problem
[0007] However, in the technique described in Patent Document 1, the surfactant not having
a micelle structure may enter the fine pores on the side walls of grooves, thereby increasing
the dielectric constant. Further, adhesion between the interlayer dielectric layer and the
wiring material may be lowered due to the micelles.
Further, in the technique described in Patent Document 2, a bulky layer may readily
be formed due to hydrogen bonding between the polyvinyl alcohol-based amphipathic
polymers. As a result, an increase in the dielectric constant or a decrease in the adhesion
between the interlayer dielectric layer and the wiring material may be caused.
[0008] Further, there may be cases in which the extra sealing composition adhering to the
wiring line cannot be removed rapidly while rrlaintaining the effective material that seals the
porous interlayer 4ielectric layer, whereby the production efficiency may be lowered.
[0009] In addition, there may be cases in which the extra material adhering to the peripheral
area, the back face or the like of the semiconductor substrate cannot be removed rapidly,
whereby the production efficiency may be lowered.
[0010] An object of the present invention is to provide a semiconductor device production
method, in which a semiconductor sealing composition that can form a thin sealing layer and
has an excellent covering property with respect to fine pores of a porous interlayer dielectric
layer is us~Q., and the sealing composition that remains on a wiring line or at a peripheral area
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or a back face of a semiconductor substrate is readily removed, whereby contamination
caused by the extra semiconductor sealing composition that exists at a wiring portion or at the
peripheral area or the back face of the semiconductor substrate is suppressed.
Another object of the present invention is to provide a rinse that is used in the
semiconductor device production method.
Means for Solving the Problem
[0011] The present inventors have made intensive investigations and, as a result, have found
that the problem can be solved by aproduction method in which a semiconductor sealing
composition that includes a specific resin and a specific rinse are used. Namely, the present
invention provides the following means.
<1> A semiconductor device production method, the method comprising:
a sealing composition application process in which a semiconductor sealing layer is
formed by applying, to at least a portion of a surface of a semiconductor substrate, a
semiconductor sealing composition that includes a resin having a cationic functional group
and a weight average molecular weight offrom 2,000 to 600,000, wherein a content of
sodium and a content of potassium are 10 mass ppb or less on an elemental basis,
respectively; and, subsequently,
a rinsing process in which the surface of the semiconductor substrate on which the
semiconductor sealing layer has been formed is rinsed with a rinse having a pH at 25°C of 6
or lower.
<2> The semiconductor device production method according to <1>, wherein the
resin having a cationic functional group and a weight average molecular weight of from 2,000
to 600,000 has a cationic functional group equivalent amount of from 43 to 430.
<3> The semiconductor device production method according to <1> or <2>, wherein
the resin having a cationic functional group and a weight average molecular weight of from
2,000 to 600,000 is polyethyleneimine or a polyethyleneimine derivative.
<4> The semiconductor device produCtion method according to anyone of <1> to
<3>, wherein a porous interlayer dielectric layer is formed on at least a portion of the surface
of the semiconductor substrate.
<5> The semiconductor device production method according to <4>, wherein the
semiconductor sealing layer is formed on the porous interlayer dielectric layer, the porous
interlayer dielectric layer has a concave groove having a width of from 10 nm to 32 nm, and
the sealing composition application process includes contacting the semiconductor sealing
composition to at least a side face of the concave groove of the porous interlayer dielectric
layer.
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<6> The semiconductor device production method according to <4> or <5>, wherein
the porous interlayer dielectric layer contains porous silica, and has a silanol residue derived
from the porous silica on a surface of the porous interlayer dielectric layer.
<7> The semiconductor device production method according to anyone of <1> to
<6>, wherein the rinse includes at least one solvent selected from the group consisting of
water, methanol, ethanol, propanol, butanol and propylene glycol monomethyl ether acetate.
<8> The semiconductor device production method according to anyone of <1> to
<7>, wherein the rinse includes at least one acid selected from the group consisting of oxalic
acid, formic acid, citric acid, p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid
and nitric acid.
<9> The semiconductor device production method according to anyone of <1> to
<8>, wherein the surface of the semiconductor substrate on which the semiconductor sealing
layer has been formed comprises a surface on which a semiconductor circuit is not formed.
<10> The semiconductor device production method according to claim <9>, wherein
the rinse, with which the surface on which a semiconductor circuit is not formed is rinsed, has
a pH at 25°C of2 or lower.
<11> The semiconductor device production method according to anyone of <1> to
<8>, wherein at least a portion of the surface of the semiconductor substrate comprises a
circuit face that is provided with a porous interlayer dielectric layer and a wiring material that
includes copper, and the rinsing process is a circuit face rinsing process in which the sealing
layer on the wiring material is removed.
<12> The semiconductor device production method according to <11>, wherein the
rinse with which the semiconductor circuit face is rinsed has a pH at 25°C of 1 or higher.
<13> The semiconductor device production method according to anyone of <1> to
<12>, wherein the cationic functional group is at least one selected from the group consisting
of a primary amino group and a secondary amino group.
<14> The semiconductor device prodhction method according to anyone of <1> to
<13>, further comprises a surface peripheral area rinsing process in which a peripheral area of
the surface of the semiconductor substrate on which the semiconductor sealing layer has been
formed is rinsed by spraying the rinse.
<15> The semiconductor device production method according to anyone of <1> to
<14>, wherein the rinse comprises at least one resin decomposer selected from the group
consisting of hydrogen peroxide and nitric acid.
<16> The semiconductor device production method according to anyone of <1> to
<15>, wheLein the circuit face rinsing process comprises rinsing under a non-oxidizing
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.. atmosphere.
<17> The semiconductor device production method according to anyone of <1> to
<16>, wherein the rinse does not include an oxidative compound.
<18> The semiconductor device production method according to anyone of <1> to
<17>, wherein the semiconductor substrate includes a silanol residue derived from a naturally
oxidized film that is formed on the surface of the substrate.
<19> A rinse for removing a semiconductor sealing layer that is derived from a resin
having a cationic functional group and a weight average molecular weight of from 2,000 to
600,000, the semiconductor sealing layer being positioned on a metal wiring of a
semiconductor circuit face or on a semiconductor substrate, and the rinse having a pH at 25°C
of 6 or lower.
<20> The rinse according to <19>, wherein the resin having a cationic functional
group and a weight average molecular weight of from 2,000 to 600,000 has a cationic
functional group equivalent amount of from 43 to 430, and the cationic functional group is at
least one selected from the group consisting of a primary amino group and a secondary amino
group.
<21> The rinse according to <19> or <20>, wherein the rinse has a pH at 25°C of 1
or higher and is used for rinsing the semiconductor circuit face.
<22> The rinse according to <19> or <20>, wherein the rinse has a pH at 25°C of 2
or lower and is used for rinsing a face ofthe semiconductor substrate on which the circuit is
not formed.
Effects of the Invention
[0012] According to the semiconductor device production method of the present invention,
it is possible to readily remove a sealing composition that can form a thin sealing layer and
exhibits an excellent sealing ability with respect to fine pores of a porous~interlayer insulating
layer, the sealing composition being attached to a portion on a wiring or a peripheral area or a
back face ofthe semiconductor substrate on which a circuit is not formed, while suppressing
contamination of the wiring portion, peripheral portion or the back face of the semiconductor
substrate with the extra semiconductor sealing composition.
DESCRIPTION OF EMBODIMENT
[0013] The semiconductor device production method of the present invention includes a
sealing composition application process in which a semiconductor sealing layer is formed by
applying, to at least a portion of a surface of a semiconductor substrate, a semiconductor
sealing composition that includes a resin having a cationic functional group and a weight
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average molecular weight of from 2,000 to 600,000, wherein a content of sodium and a
content of potassium are 10 mass ppb or less on an elemental basis, respectively; and,
subsequently, a rinsing process in which the surface of the semiconductor substrate on which
the semiconductor sealing layer has been formed is rinsed with a rinse having a pH at 25°C of
6 or lower.
As necessary, the semiconductor device production method ofthe present invention
further includes one or more other processes between the sealing composition application
process and the rinsing process, or after the rinsing process.
The term "the face on which the semiconductor sealing composition is formed" used
in the present invention includes anyone of a front face of the semiconductor substrate (a
circuit face provided with a porous interlayer dielectric layer and a wiring material including
copper), a back face of the semiconductor substrate (a face on which a semiconductor circuit
is not formed) or a peripheral area ofthe front face (a face on which a semiconductor circuit is
formed), or a combination thereof.
[0014] 1. Sealing Composition Application Process
The sealing composition application process according to the present invention
includes an operation of applying, to at least a portion of a surface of a semiconductor
substrate, a semiconductor sealing composition that includes a resin having a cationic
functional group and has a weight average molecular weight of from 2,000 to 600,000,
wherein a content of sodium and a content of potassium are 10 ppb or less on an elemental
basis.
[0015]
The semiconductor substrate according to the present invention is not specifically
restricted and may be any semiconductor substrate that is commonly used. Specific
examples include a silicon wafer and a silicon wafer on which a circuit such as a transistor is
formed.
[0016] '
The pnrous interlayer dielectric layer according to the present invention is not
particularly limited as far as it is made of a material having a low dielectric constant and a
porous structure. Preferably, the porous interlayer dielectric layer includes porous silica and
has, on its surface, a silanol residue derived from the porous silica. By the interaction
between the silanol residue and the cationic functional group contained in the resin, a thin
layer of the resin is formed such that the resin covers fine pores on the interlayer dielectric
layer.
[0017] Th~ porous silica according to the present invention is not specifically restricted and
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• may be any porous silica that is generally used for an interlayer dielectric layer of a
semiconductor device. Examples of the porous silica include an oxide having uniform
meso-fine pores that is obtained by a method utilizing self-organization of an organic
compound and an inorganic compound, which is caused by hydrothermal synthesis in a sealed
heat-resistant container including silica gel, a surfactant, and the like, as described in the
International Publication No. WO 91/11390; and a porous silica produced from a condensate
of an alkoxy silane and a surfactant, as described in Nature, 1996, vol. 379 (page 703) or
Supramolecular Science, 1998, vol. 5 (page 247 etc.)
In particular, an interlayer dielectric layer formed from the porous silica described in
WO 20091123104 is preferable.
[0018] The porous interlayer dielectric layer can be formed, for example, by coating a
surface of a silicon wafer with the composition for forming porous silica as described above,
and subjecting the same to a heat treatment or the like, as necessary.
[0019] The porous interlayer dielectric layer according to the invention may have a concave
groove having a width of from 10 run to 32 run. The concave groove is formed mainly for
the purpose of embedding a wiring material therein, and may be formed by a common etching
process for a semiconductor. The term "side face of a concave groove" refers to a face that
is formed so as to be substantially orthogonal with respect to a plane that is parallel to the
substrate. Further, the porous interlayer dielectric layer may have a pore that reaches a
wiring line or the like that is directly formed on the silicon wafer.
[0020] As described below, by contacting the semiconductor sealing composition to the
concave groove, diffusion of a component included in the wiring material into pores of the
porous interlayer dielectric layer can be effectively suppressed while embedding the wiring
material into the concave groove.
[0021] The process of forming a concave groove having a width of from 10 run to 32 run or
a pore in the interlayer dielectric layer can be carried out in accordance with the process
conditions that are common for manufacturing semiconductor devices. For example, a
groove having a d~sired pattern may be formed by forming a hard mask and a photoresist on
the interlayer dielectric layer, and carrying out etching according to a pattern of the
photoresist. Further, as described above, when the porous interlayer dielectric layer includes
porous silica, surfaces of the porous silica are scraped during the formation of the concave
groove. As a result, the density of silanol groups at the surface tends to be increased.
[0022]
A circuit is formed by depositing a wiring material that contains copper between
elements SQch as a transistor formed on the silicon wafer. The wiring formation process can
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be carried out according to known process conditions. For example, a copper wiring line is
formed directly on a silicon wafer, or on an interlayer dielectric layer having a concave
groove or a pore as described above, by a metal CVD method, a sputtering method or an
electroplating method, and then the film is smoothed by chemical mechanical polishing
(CMP). As necessary, a multilayer structure can be obtained by forming a cap film on the
surface of the film and forming a hard mask thereon, and repeating the process of forming a
porous interlayer dielectric layer and'the process of forming a wiring line.
[0023]
The semiconductor sealing composition according to the present invention is used,
for example, to form a resin layer that covers fine pores formed on the porous interlayer
dielectric layer. The semiconductor sealing composition includes at least one resin having a
cationic functional group and a weight average molecular weight of from 2000 to 600000.
The content of sodium and the content of potassium in the semiconductor sealing composition
are 10 ppb or less on an elemental basis, respectively. Preferably, the semiconductor sealing
composition hasa volume average particle diameter measured by a dynamic light scattering
method of 10 nm or less.
[0024] When a semiconductor sealing composition having the composition as specified
above is applied onto a porous interlayer dielectric layer having a porous structure, for
example, the cationic functional group ofthe resin is adsorbed to the interlayer dielectric layer
at multiple points, whereby the fine pores that exist at a surface of the interlayer dielectric
layer are covered with a resin layer. As a result, diffusion of a metal component into the
porous interlayer dielectric layer can be suppressed. Further, since the resin layer formed
from the resin is a thin layer (for example, 5 nm or less), adhesion between the interlayer
dielectric layer and the wiring material, which is formed on the interlayer dielectric layer via
the resin layer, is excellent, and the change in dielectric constant can be sblppressed.
[0025] [Resin]
The semiconductor sealing compositi~n according to the present invention includes
at least one resin having a cationic functional group and a weight average molecular weight of
from 2,000 to 600,000.
[0026] The resin has at least one kind of cationic functional group, but the resin may further
have an anionic functional group or a nonionic functional group, as necessary. Further, the
resin may have a repeating unit structure having a cationic functional group, or may have a
random structure formed from a monomer that constitutes the resin that polymerizes in a
branched form, rather than a specific repeating unitstructure. J In the present invention, from
the viewpoLnt of suppressing diffusion of a metal component, the resin preferably has a
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random structure formed from a monomer that constitutes the resin that polymerizes in a
branched form, rather than a specific repeating unit structure.
[0027] The cationic functional group is not particularly limited as far as it is a functional
group that can be positively charged. Examples of the cationic functional group include an
amino group and a quaternary ammonium group. Among them, from the viewpoint of
suppressing diffusion of a metal component, the cationic functional group is preferably at
least one selected from the group consisting of a primary amino group and a secondary amino
group.
The nonionic functional group may be a hydrogen bond-accepting group or may be a
hydrogen bond-donating group. Examples ofthe nonionic functional group include a
hydroxyl group, a carbonyl group and an ether group.
The anionic functional group is not particularly limited as far as it is a functional
group that can be negatively charged. Examples of the cationic functional group include a
carboxyl group, a sulfonic acid group, and a sulfate group.
[0028] Since the resin has a cationic functional group in a molecule, the resin can suppress
diffusion of a metal component. Further, from the viewpoint of suppressing diffusion of a
metal component, the resin preferably has a high cation density. Specifically, the cationic
functional group equivalent weight ofthe resin is preferably from 43 to 430, more preferably
from 200 to 400.
When the surface of the porous interlayer dielectric layer is subjected to a
hydrophobication treatment by a known method, for example, by a method described in WO .
.04/026765, WO 06/025501 and the like, the density ofpolar groups at the surface is decreased.
Therefore, a cationic functional group equivalent weight of from 200 to 400 is also preferred.
In the specification, the term "cationic functional group equivalent weight" refers to
a weight average molecular weight per cationic functional group, and is a-value (Mw/n)
obtained by dividing the weight average molecular weight (Mw) ofthe resin by the number of
cationic functional groups included in one mofecule of the resin (n). The greater the cationic
functional group equivalent weight is, the smaller the density of cationic functional groups is.
The smaller the cationic functional group equivalent weight is, the greater the density of
cationic functional groups is.
[0029] \\!'hen the resin used in the present invention has a repeating unit structure having a
cationic functional group (hereinafter, also referred to as a "specific unit structure"), the
cationic functional group may be included in the specific unit structure as at least a portion of
a main chain, or may be included as at least a portion of a side chain, or may be included as at
least a portion of a main chain and at least a portion of a side chain.
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When the specific unit structure includes two or more cationic functional groups, the
two or more cationic functional groups may be the same or different from each other.
Further, -it is preferable that the cationic functional group is incorporated such that the
ratio of the length of a main chain of a specific unit structure with respect to the average
distance between absorption points of cationic functional groups (for example, silanol
residues) that exist on the porous interlayer dielectric layer (hereinafter, also referred to as a
"relative distance between cationic functional groups) is from 0.08 to 1.2, more preferably
from 0.08 to 0.6. In that case, the resin tends to adsorb at multiple points to the porous
interlayer dielectric layer more efficiently.
[0030] In the present invention, from the viewpoint of adsorptivity with respect to the
interlayer dielectric layer, the specific unit structure preferably has a molecular weight of from
30 to 500, more preferably from 40 to 200. The molecular weight ofthe specific unit
structure refers to the molecular weight of a monomer that constitutes the specific unit
structure.
From the viewpoint of adsorptivity with respect to the interlayer dielectric layer, the
specific unit structure in the present invention preferably has a relative distance between
cationic functional groups of from 0.08 to 1.2 and a molecular weight of from 30 to 500, and
more preferably has a relative distance between cationic functional gro-ups of from 0.08 to 0.6
and a molecular weight of from 40 to 200.
[0031] In the present invention, specific examples of the specific unit structure that includes
a cationic functional group include a unit structure derived from ethyleneimine, a unit
structure derived from allylamine, a unit structure derived from a diallyldimethyl ammonium
salt, a unit structure derived from vinylpyridine, a unit structure derived from lysine, a unit
structure derived from methylvinylpyridine, and a unit structure derived from p-vinylpyridine.
Among them, from the viewpoint of adsorptivity with respect to theintedayer dielectric layer,
at least one selected from the group consisting of a unit structure derived from ethyleneimine
and a unit structure derived from allylamine i~'preferable.
[0032] The resin may further include at least one selected from the group consisting of a unit
structure that includes a nonionic functional group and a unit structure that includes an
anionic functional group.
Specific examples of the unit structure that includes a nonionic functional group
include a unit structure derived from vinyl alcohol, a unit structure derived from alkylene
oxide, and a unit structure derived from vinyl pyrrolidone.
[0033] Specific examples ofthe unit structure that includes an anionic functional group
include a unit structure derived from styrenesulfonic acid, a unit structure derived from
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vinylsulfuric acid, a unit structure derived from acrylic acid, a unit structure derived from
methacrylic acid, a unit structure derived from maleic acid, and a unit structure derived from
fumaric acid.
[0034] In the present invention, when the resin includes two or more kinds of specific unit
structures, the difference of the specific unit structures may be any of the kind or the number
of polar groups included therein, the molecular weight, or the like. Further, the two or more
kinds of specific unit structures may be included in the form of a block copolymer or a
random copolymer.
[0035] The resin may further contain at least one kind of repeating unit structure other than
the specific unit structure described above (hereinafter, also referred to as a "second unit
structure"). When the resin includes a second unit structure, the specific unit structure and
the second unit structure may be included in the form of a block copolymer or a random
copolymer.
The second unit structure is not particularly limited as far as the unit structure is
derived from a monomer that can polymerize with a monomer that constitutes the specific
unit structure. Examples of the second unit structure include a unit structure derived from an
olefin.
[0036] When the resin in the present invention does not have a specific repeating unit
structure but has a random structure formed from a monomer that constitutes the resin that
polymerizes in a branched manner, the cationic functional group may be included as at least a
portion of a main chain, at least a portion of a side chain, or at least a portion of a main chain.
and at least a portion of a side chain.
Examples of the monomer that can constitute such a resin include ethyleneimine and
derivatives thereof.
[0037] Specific examples of the resin that includes a cationic functional-group in the present
invention include polyethyleneimine (PEl), polyallylamine (PAA),
polydiallyldimethylammonium (PDDA), polyVinylpyridine (PVP), polylysine,
polymethylpyridylvinyl (PMPyV), protonated poly(p-pyridyl vinylene) (R-PHPyV), and
derivatives thereof. Among them, polyethyleneimine (PEl) or a derivative thereof,
polyallylamine (PAA) and the like are preferable, and polyethyleneimine (PEl) or a derivative
thereof is more preferable.
[0038] Polyethyleneimine (PEl) can be produced by polymerizing ethyleneimine according
to a method that is commonly used. The polymerization catalyst, the polymerization
conditions, and the like may also be selected as appropriate from those generally used in the
polymerization of ethyleneimine. Specifically, for example, the reaction can be conducted in
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• the presence of an effective amount of an acid catalyst, such as hydrochloric acid, at a
temperature of from O°C to 200°C. Further, ethyleneimine may be subjected to addition
polymerization with polyethyleneimine as the basis. Moreover, the polyethyleneimine in the
present invention may be a homopolymer of ethyleneimine, or may be a copolymer of
ethyleneimine and a compound that can copolymerize with ethyleneimine, such as an amine.
With regard to a method for producing polyethyleneimine, for example, Japanese Patent
Application Publication (JP-B) Nos. 43-8828 and 49-33120 and the like may be referred to.
Further, the polyethyleneimine in the present invention may be obtained by using
crude ethyleneimine that is obtained from monoethanol amine. With regard to the specific
examples of such polyethyleneimine, for example, JP-A No. 2001-2123958 and the like may
be referred to.
[0039] The polyethyleneimine, produced by a process as described above, has a complicated
structure having not only a partial structure in which ethyleneimine is ring-opened and
connected to form a straight chain, but also a partial structure in which the ethyleneimine is
connected to form a branched chain, a partial structure in which the straight-chain partial
structures are connected by crosslinking, and the like. By using a resin having a cationic
functional group of a structure as described above, multipoint adsorption of the resin can be
more efficient. Further, a sealing layer may be formed more effectively via interaction
among the resin.
[0040] A polyethyleneimine derivative is also suitably used. The polyethyleneimine
derivative is not particularly limited as far as it can be produced from polyethyleneimine.
Specific examples ofthe polyethyleneimine derivative include a polyethyleneimine derivative
obtained by introducing an alkyl group (preferably having from 1 to 10 carbon atoms) or an
aryl group into polyethyleneimine, and a polyethyleneimine derivative obtained by
introducing a crosslinkable group, such as a hydroxyl group, into polyethyleneimine.
The polyethyleneimine derivatives can be produced by an ordinary method from
polyethyleneimine. Specifically, for example, the polyethyleneimine derivatives can.be
produced by a method described in JP-A No. 6-016809 and the like.
[0041] The polyethyleneimine or a derivative thereof in the present invention may be a
commerciallyavailableproduct. For example, polyethyleneimine and derivatives thereof
available from Nippon Shokubai Co., Ltd., BASF and the like may be selected and used.
[0042] The weight average molecular weight of the resin in the present invention is from
2,000 to 600,000, preferably from 2,000 to 300,000, more preferably from 2,000 to 100,000,
yet more preferably from 10,000 to 80,000, and yetmore preferably from 20,000 to 60,000.
That the wejght average molecular weight is from 2,000 to 600,000 means that the molecular
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weight is adjusted to fall within this range, in view of sealing of fine pores ofthe porous
interlayer dielectric layer and the dielectric constant.
For example, when the semiconductor sealing composition according to the
invention is applied to production of a semiconductor device in which the wiring interval is
32 nm or less and the diameter of fine pores on the interlayer dielectric layer is approximately
2 nm, and the weight average molecular weight ofthe resin is more than 600,000, the size of
the resin is greater than the wiring interval and the resin is prevented from entering the
concave groove in which the wiring material is to be embedded, whereby the fine pores of
side faces of the groove are not sufficiently covered. When the weight average molecular
weight of the resin is less than 2,000, the size of the resin molecule is smaller than the
diameter of fine pores on the interlayer dielectric layer and the resin molecule enters the fine
pores on the interlayer dielectric layer, whereby the dielectric constant of the interlayer
dielectric layer is increased. Further, the adsorption of the resin may not occur at multi
points.
The weight average molecular weight is measured with a GPC equipment that is
commonly used for measuring the molecular weight of a resin. The weight average
molecular weight described in the specification is measured under the following conditions.
GPC equipment: GPC-IOl, manufactured by Shodex Co., Ltd:
Column: ASAHIPAK GF-7M HQ
Eluent: 0.5M NaN03 + 0.5M AcOH solution
Flow rate: 1 mL/min.
[0043] It is also preferable that the resin has a critical micelle concentration in an aqueous
solvent of 1% by mass or more, or that the resin is a resin that does not substantially form a
micelle structure. The expression "does not substantially form a micelle structure" as used
herein refers to that a micelle is not formed under general conditions, such as in an aqueous
solvent at an ordinary temperature, i.e., the critical micelle concentration cannot be measured.
With such a resin, a thin resin layer having a tllickness of a molecule level (for example, 5 nm
or less) can be formed, and an increase in the dielectric constant of the interlayer dielectric
layer can be effectively suppressed. Further, adhesion between the interlayer dielectric layer
and the wiring material may be enhanced more effectively.
[0044] Moreover, the resin in the present invention is preferably a polyethyleneimine having
a weight average molecular weight of from 2,000 to 600,000 and has a cationic functional
group equivalent weight of from 43 to 430, and more preferably a polyethyleneimine having a
weight average molecular weight of from 10,000 to 80,000 and has a cationic functional
group equiyalent weight of from 200 to 400. In accordance with the embodiment as
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• described above, diffusion of a metal component into the interlayer dielectric layer may be
suppressed more effectively, and adhesion between the interlayer dielectric layer and the
wiring material may be further enhanced.
[0045] The content of the resin in the semiconductor sealing composition according to the
invention is not particularly limited, and the content of the resin may be, for example, from
0.01% by mass to 1.0% by mass, preferably from 0.02% by mass to 0.3% by mass. Further,
the content of the resin in the composition can be adjusted based on the area and the fine pore
density of the plane on which a resin layer is to be formed with the semiconductor sealing
composition according to the invention.
[0046] In the semiconductor sealing composition according to the invention, the content of
sodium and the content ofpotassium are 10 ppb or less on an elemental basis, respectively.
The term "10 ppb or less" refers to that sodium and potassium are not positively contained.
When the content of sodium or potassium exceeds 10 ppb on an elemental basis, a leak
current may be generated.
[0047] The semiconductor sealing composition according to the invention may include a
solvent in addition to the resin, as necessary, and a solvent is contained at least in the sealing
composition application process. The solvent in the present invention is not particularly
limited as far as it uniformly dissolves the resin, and is difficult to fomi a micelle. Examples
of such solvents include water (preferably, ultrapure water) and water-soluble organic solvents
(for example, alcohols). In the present invention, from the viewpoint ofmicelle formability,
water or a mixture of water and a water-soluble organic solvent is preferably used as the
solvent.
[0048] The boiling point of the solvent is not particularly limited, but the boiling point is
preferably 210°C or lower, more preferably 160°C or lower. When the boiling point of the
solvent is within the above range, for example, in a case in which a rinsing process or a drying
process is provided after the process of applying the semiconductor sealing composition
according to the present invention to the interlayer dielectric layer, as described below, the
solvent can be r.emoved without significantly affecting the insulating properties ofthe
interlayer dielectric layer, or at a low temperature that does not cause exfoliation of the
sealing composition from the interlayer dielectric layer, thereby forming a semiconductor
sealing layer. The term "semiconductor sealing composition" is used also to refer to a
sealing composition that forms these semiconductor sealing layers.
[0049] Moreover, the semiconductor sealing composition according to the invention may
further contain, as necessary, cations such as cesium ions as long as the effect of the invention
is not impaired. When the sealing composition includes cations of cesium or the like, it
14
-
• becomes easier for the resin in the semiconductor sealing composition to spread over the
interlayer dielectric layer more uniformly.
[0050] Further, it is preferable that the semiconductor sealing composition according to the
invention is not added with a compound that decomposes or dissolves the interlayer dielectric
layer. Specifically, for example, especially in a case in which the main material of the
interlayer dielectric layer is an inorganic compound such as silica, when a fluorine-containing
compound or the like is incorporated in the composition according to the invention, there may
be a case in which the interlayer dielectric layer is dissolved and its insulating property is
impaired, thereby causing an increase in the dielectric constant.
[0051] It is preferable that the semiconductor sealing composition according to the invention
contains only compounds that have a boiling point of 210°C or lower, preferably 160°C or
lower, or compounds that do not exhibit decomposability even when heated up to 250°C.
The expression "compounds that do not exhibit decomposability even when heated
up to 250°C" refers to compounds having a change in mass after being maintained at 250°C
under nitrogen for one hour, with respect to the mass measured at 25°C, of less than 50%.
[0052] It is preferable that the semiconductor sealing composition according to the invention
preferably has a volume average particle diameter as measured by a dynamic light scattering
method of 100m or less. The expression "having a volume average particle diameter of 10
om or less" refers to that large particles are not positively contained in view of adhesion.
When the volume average particle diameter exceeds 100m, there may be a case in which
adhesion with respect to the wiring material is lowered, or diffusion of a metal component
into the interlayer dielectric layer is not sufficiently suppressed.
In the present invention, the volume average particle diameter can be measured using
ELSZ-2, manufactured by Ootsuka Denshi Co., Ltd., at a temperature of from 23°C to 26°C,
in accordance with a dynamic light scattering method (a method for analyzing the
time-dependent fluctuation in scattering light observed by the dynamic light scattering
method, using photon correlation, for example: under the conditions of a cumulative number
of 70, a number o~ repetition of 1, and the like).
[0053] In the present invention, the case in which the volume average particle diameter
exceeds 100m refers to, specifically, a case in which a micelle (having an average particle
diameter of 100m or more) is formed in the composition, or a case in which abrasive particles
of a metal oxide, which are used for polishing (chemical mechanical polishing) copper to
form wiring lines or the like, are included in the composition, or the like.
When a micelle having a large particle diameter is formed in the semiconductor
sealing composition, for example, in a case of applying the semiconductor sealing
15
-
• composition according to the invention to the manufacture of a semiconductor device having
a wiring interval of 32 nm of less, there is a case in which the resin that constitutes the
semiconductor sealing composition cannot sufficiently enter concave grooves in which the
wiring material is to be embedded. As a result, fine pores at side faces of the grooves may
not be sufficiently sealed.
[0054] The pH ofthe semiconductor sealing composition according to the invention is not
particularly limited, but it is preferably equal to or higher than the isoelectric point of the
interlayer dielectric layer, from the viewpoint ofthe adsorptivity of the resin with respect to
the interlayer dielectric layer. Further, in a case in which the resin has a cationic functional
group as a polar group, the pH of the semiconductor sealing composition is preferably within
a range ofthe pH in which the cationic functional group is in a state of a cation. When the
semiconductor sealing composition has a pH as specified above, the resin may adsorb to the
interlayer dielectric layer more efficiently, due to the electrostatic interaction between the
interlayer dielectric layer and the resin.
[0055] The isoelectric point of the interlayer dielectric layer is an isoelectric point of the
compound that constitutes the interlayer dielectric layer. For example, when the compound
that constitutes the interlayer dielectric layer is porous silica, the isoelectric point is around
pH 2 (at 25°C).
The "range ofpH in which the cationic functional group is in a state of a cation"
refers to that the pH of the semiconductor sealing composition is equal to or lower than the
pKb of the resin that includes the cationic functional group. For example, when the resin .
that includes a cationic functional group is polyallylamine, the pKb is from 8 to 9, and when
the resin that includes a cationic functional group is polyethyleneimine, the pKb is from 7 to
11.
Namely, in the present invention, the pH ofthe semiconductor s@aling composition
can be selected as appropriate, depending on the kind of the compound that constitutes the
interlayer dielectric layer and the kind ofthe r~sin. For example, the pH is preferably from 2
to 11, and preferably from 7 to 11. The pH (at 25°C) is measured with a generally used pH
meter.
[0056]
The method of applying the semiconductor sealing composition according to the
invention to the porous dielectric layer is not particularly limited, and a generally used
method can be employed. Examples ofthe method include a method of contacting a
semiconductor sealing composition with a porous dielectric layer by, for example, a dipping
method (se~, for example, U.S. Patent No. 5208111), a spraying method (see, for example,
16
-
• ScWenoffet aI., Langmuir, 16(26),9968,2000 or Izuquierdo et aI., Langmuir, 21(16), 7558,
2005), a spin coating method (see, for example, Lee et aI., Langmuir, 19(18), 7592,2003 or J.
Polymer Science, part B, polymer physics, 42,3654,2004), or the like.
[0057] In the semiconductor device production method ofthe invention, by applying the
semiconductor sealing composition that includes the resin, and by appropriately drying the
same by a generally used method, a thin semiconductor sealing layer of the resin can be
formed on the interlayer dielectric layer. The thickness of the semiconductor sealing layer is
not particularly limited, but the thickness is, for example, from 0.3 nm to 5 nm, and preferably
from 0.5 nm to 2 nm.
[0058] Further, it is preferable that the concentration of the resin included in the
semiconductor sealing composition used in the sealing composition application process
according to the present invention is less than the critical micelle concentration of the resin.
In that case, the resin can be applied to the interlayer dielectric layer in the form of a thin
layer (for example, 5 nm ofless, preferably 2 nm or less), and an increase in the dielectric
constant can be suppressed.
[0059] Moreover, as a method of conta~tingthe semiconductor sealing composition with the
side face of a concaved groove of the interlayer dielectric layer, the above-described dipping
method, spraying method, or spin coating method can be employed.
After the application of the semiconductor sealing composition, the resin may be
crosslinked and polymerized.
[0060] 2. Rinsing Process
The semiconductor production method according to the present invention includes a
process of rinsing to remove the sealing layer, by applying a rinse having a pH of 6 or lower
at 25°C, after the above-described sealing composition application process.
~
Hereinafter, a process of removing the semiconductor sealing layer formed on the
surface of the porous interlayer dielectric laye; disposed on the surface of the semiconductor
substrate (circuit face rinsing process), is described.
In the above-described sealing composition application process, a semiconductor
sealing layer is formed on the surface of the porous interlayer dielectric layer disposed on the
surface of the semiconductor substrate. Here, when a sealing composition is applied, in a
case in which' a porous interlayer dielectric layer and a wiring material including copper are
provided on at least a portion of a surface ofthe semiconductor substrate, or in a case in
which a sealing layer which does not effectively seal the porous interlayer dielectric layer
exfoliates during the semiconductor manufacturing process such as the wiring forming
17
-
• process and adheres onto the wiring material, or the like, a semiconductor sealing layer may
be formed on the wiring material. Accordingly, in this circuit face rinsing process, the extra
semiconductor sealing composition that has adhered to the wiring material is rapidly removed
by rinsing, while maintaining the effective semiconductor sealing composition that seals the
porous interlayer dielectric layer.
[0061] The first rinse (cleaning agent) according to the present invention, which is used in
the circuit face rinsing process, is a solution having the upper limit of the pH at 25°C of 6 or
lower, preferably 5 or lower, and the lower limit of the pH of preferably 1 or higher, more
preferably 2 or higher, and more preferably from 1 to 5, yet more preferably from 2 to 5, yet
more preferably from 2 to 3.
The first rinse is a liquid that dissolves or decomposes the composition in order to
rapidly wash and remove the above-described extra semiconductor sealing composition
(semiconductor sealing layer). The first rinse is required to rapidly remove the
semiconductor sealing composition, in order to improve the manufacturing efficiency of the
semiconductor, and not to contaminate or destroy the circuit materials such as the porous
dielectric layer. With the above pH range, in which copper oxide is dissolved but the porous
dielectric layer hardly dissolves, the interaction between the porous dielectric layer and the
sealing composition material is not greatly impaired.
[0062] Namely, the first rinse hardly destroys the porous layer dielectric layer that is formed
from silica or the like, and has a function of suppressing exfoliation of the effective sealing
composition that seals fine pores ofthe porous dielectric layer, and rapidly removing the extra
sealing composition that has adhered to the wiring material.
[0063] Further, since an oxide ofthe wiring material also exists on the wiring material, in
addition to the sealing composition, and causes separation ofthe.wiring material from the low
dielectric constant material or separation between the wiring materials. ~Therefore, it is
known that a process of removing the oxide is necessary. The first rinse dissolves an oxide
film on the wiring material, specifically a copper oxide film when the wiring material.
includes copper~ and removes the extra sealing composition together with the oxide film.
Accordingly, the extra oxide film on the wiring material can be removed together with the
extra sealing composition while suppressing exfoliation of the effective sealing composition
that seals the fine pores of the porous dielectric layer.
[0064] The first rinse preferably contains a solvent having a high polarity. This is because
the semiconductor sealing composition according to the invention has a high polarity as
described above and easily dissolves in a solvent having a high polarity, thereby improving
the rinsing_efficiency of the rinse. Specifically, it is preferable that the first rinse contains a
18
-
• polar solvent such as water, methanol, ethanol, propanol, butanol, or propylene glycol
monomethyl ether acetate. Such polar solvents do not significantly impair the interaction
between the porous dielectric layer and the sealing composition.
The first rinse may be applied with heat or ultrasonic waves.
[0065] The first rinse can be produced by adding an acid to the solvent to adjust its pH to
be within the above range. The acid that may be used in the present invention is not
particularly limited, and an acid that does not contaminate or destroy the porous interlayer
dielectric film and is less likely to remain on the semiconductor substrate may be used.
Specific examples of the acid include organic acids such as monocarboxylic acids such as
formic acid and acetic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid,
glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid and phthalic acid,
tricarboxylic acids such as trimellitic acid and tricarballylic acid, oxymonocarboxylic acids
such as hydroxybutyric acid, lactic acid and salicylic acid, oxydicarboxylic acids such as
malic acid and tartaric acid, oxytricarboxylic acids such as citric acid, aminocarboxylic acids
such as aspartic acid and glutamic acid, p-toluenesulfonic acid, and methanesulfonic acid; and
inorganic acids such as hydrochloric acid, nitric acid and phosphoric acid. Among them, at
least one selected from the group consisting of oxalic acid, formic acid, citric acid,
p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid and nitric acid is preferable.
[0066] From the viewpoint of suppressing oxidization of the wiring material formed by
including copper or the like, the first rinse preferably contains a reducing agent or a
compound having a deoxidation action. An example ofthe reducing agent or compound
having a deoxidation action that may be used in the first rinse is formalin.
[0067] Further, from the viewpoints of preventing cleavage of carbon-carbon bonds or the
like in the resin of the sealing composition and preventing exfoliation ofthe effective sealing
layer that seals the fine pores ofthe porous dielectric layer, the content of-the oxidative
compound (for example, hydrogen peroxide or nitric acid) in the first rinse is preferably 10%
by mass or lower. It is more preferable that the first rinse does not contain an oxidative
compound.
[0068] Further, the first rinse preferably has an ionic strength of 0.003 or more, more
preferably 0.01 or more. Since the semiconductor sealing composition contains a resin that
has a cationic functional group and has a high polarity, as described above, the rinse can
readily dissolve the resin without significantly impairing the interaction between the porous
dielectric layer and the sealing composition, when the pH and the ionic strength are within the
above ranges. There is no particular limitation as to the upper limit of the ionic strength, as
long as an ionic compound can be dissolved. The ionic strength is expressed by the
19
-
• following formula.
Ionic strength = 1/2 x ~(c x Z2)
(wherein, c represents a molar concentration of the ionic compound included in the
rinse, and Z represents an ionic valence of the ionic compound included in the rinse.)
[0069] In order to adjust the ionic strength, an ionic compound such as an organic base such
as ammonia, pyridine or ethylamine may be added, for example, other than the acid as
described above, as necessary.
It is also possible to add a polymer that traps copper ions (for example,
polyethyleneimine) after removing copper.
[0070] The amounts of the solvent, acid, reducing agent, ionic compound, and the like,
which may be incorporated in the first rinse, can be adjusted as appropriate such that the pH
and the ionic strength of the rinse each fall within the above ranges.
[0071] The first rinse can be prepared by mixing the solvent, acid, reducing agent, ionic
compound, and the like. In order to prevent contamination of the semiconductor circuit, it is
preferable to prepare the rinse under a clean environment such as in a clean room, or to
remove, after the preparation of the rinse, components that may contaminate the
semiconductor circuit by means of purification, filtration, or the like.
[0072] In the present invention, by the application of the first rinse, the extra sealing
composition that has adhered to the wiring material can be rapidly removed by rinsing, while
maintaining the effective material that seals the porous interlayer dielectric layer. Further, as
described above, an oxide ofthe wiring material may be removed, whereby separation of the.
wiring material from the low dielectric constant material or separation between the wiring
materials can be suppressed.
[0073] The circuit face rinsing process is preferably conducted under a non-oxidizing
atmosphere. By conducting rinsing under a non-oxidizing atmosphere, it is possible to
prevent excessive removal of copper that is caused by repeated removal of copper oxide on
the wiring surface that has existed before rinsing and further oxidization of copper that is to
be dissolved with the rinse. A non-oxidizing atmosphere can be created by, for example,
using a reducing atmosphere gas.
[0074] The method of rinsing the circuit face ofthe semiconductor substrate according to
the invention is not particularly limited, as far as the first rinse is used therein, and rinsing
may be conducted by a generally used method.
The time for rinsing the circuit face is not particularly limited. For example, when
the rinse has a pH at 25°C of 5, the rinsing time is preferably from 0.1 minutes to 60 minutes,
more prefer.ably from 0.1 minutes to 10 minutes.
20
-
• [0075]
Hereinafter, a process of rinsing the "back face" of the semiconductor substrate,
which is opposite to the face on which the porous interlayer dielectric layer formed, with a
rinse is described.
[0076] In the sealing composition application process as described above, a semiconductor
sealing layer is formed on the surface of the porous interlayer dielectric layer that is disposed
on the surface of the semiconductor substrate. During the process, a semiconductor sealing
layer may be formed also at peripheral portions of the front face of the semiconductor
substrate, where a circuit such as an interlayer dielectric layer is not formed and the
semiconductor substrate (when a silicon wafer is used as the semiconductor substrate, a
naturally oxidized film formed on the surface ofthe silicon wafer) is exposed, or at the back
face of the semiconductor substrate on which a circuit such as a porous interlayer dielectric
film is not formed.
The extra sealing layer that does not seal the porous interlayer dielectric layer may
exfoliate during the semiconductor production process such as the wiring forming process as
described above, thereby contaminating the semiconductor substrate. Accordingly, it is
necessary to provide a rinsing process for removing the extra semiconductor sealing layer
after the sealing composition application process, at least for the back face of the
semiconductor substrate.
Further, the back face rinsing includes a process of rinsing a portion at an edge
portion of the wafer having a round shape that is positioned between the back face and the
face on which the porous interlayer dielectric layer is formed (bevel rinsing).
[0077] The second rinse according to the invention, which is used in the back face rinsing
process, is a liquid that dissolves or decomposes the composition in order to rapidly wash and
remove the extra semiconductor sealing composition (semiconductor seal.ing layer) as
described above. It is necessary that the second rinse rapidly removes the semiconductor
sealing composition in order to improve the efficiency of producing semiconductors, and that
the second rinse does not contaminate or destroy the circuit materials such as the porous
dielectric layer.
[0078] There are three possible methods for removing the semiconductor sealing
composition with the second rinse, which are: 1) weakening the interaction between the
semiconductor sealing composition and the semiconductor substrate to which the
semiconductor sealing composition is adsorbed; 2) dissolving the semiconductor sealing
composition having a high polarity by increasing the ionic strength of the rinse; and 3)
decomposiIlg the semiconductor sealing composition. These three methods may be
21
-
• combined with each other.
[0079] From the viewpoint of "1)" described above, the second rinse has a pH at 25°C of 6
or lower, preferably 5 or lower, more preferably from 0 to 2.5, even more preferably from 0 to
2.0. When a silicon wafer is used as the semiconductor substrate, a naturally oxidized film
is formed on the back face of the semiconductor substrate, which is to be washed with the
rinse, or at the peripheral area ofthe front face of the semiconductor substrate described
below. Therefore, a great number of silanol groups exist at the surfaces. The density of the
silanol groups derived from the naturally oxidized film is not limited, but may be generally a
density of about 5/100 A2
. It is assumed that the cationic functional group ofthe
semiconductor sealing composition according to the invention forms an interaction with the
silanol group and is fixed. Therefore, by rinsing with a rinse having a pH of 5 or lower, or
preferably with a rinse having a pH that is equal to or lower than the isoelectric point of the
silanol residue, the interaction may be weakened and the extra semiconductor sealing
composition may be efficiently removed.
[0080] The acid that can be used for adjusting the pH of the second rinse to be within the
above range is not particularly limited, as long as it does not contaminate or destroy the
porous interlayer dielectric layer and is less likely to remain on the semiconductor substrate.
Specific examples of the acid include organic acids such as monocarboxylic acids such as
formic acid and acetic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid,
glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid and phthalic acid,
tricarboxylic acids such as trimellitic acid and tricarballylic acid, oxymonocarboxylic acids .
such as hydroxybutyric acid, lactic acid and salicylic acid, oxydicarboxylic acids such as
malic acid and tartaric acid, oxytricarboxylic acids such as citric acid, aminocarboxylic acids
such as aspartic acid and glutamic acid, p-toluenesulfonic acid, and methanesulfonic acid; and
inorganic acids such as hydrochloric acid, nitric acid and phosphoric acid: Among them, at
least one selected from the group consisting of oxalic acid, formic acid, citric acid,
p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid and nitric acid is preferable.
[0081] Further, from the viewpoint of "2)" described above, the second rinse preferably has
an ionic strength of 0.003 or more, more preferably 0.01 or more. Namely, since the
semiconductor sealing composition contains a resin that has a cationic functional group and
has a high polarity, as described above, the rinse can readily dissolve the resin without
significantly impairing the interaction between the porous dielectric layer and the sealing
composition, when the pH and the ionic strength are within the above ranges. There is no
particular limitation as to the upper limit of the ionic strength, as long as an ionic compound
can be diss.Qlved. The ionic strength is expressed by the following formula.
22
•
Ionic strength = 1/2 x l:(c x Z2)
(wherein, c represents a molar concentration of the ionic compound included in the
rinse, and Z represents an ionic valence ofthe ionic compound included in the rinse.)
[0082] In order to adjust the ionic strength, an ionic compound such as an organic base such
as ammonia, pyridine or ethylamine may be added, for example, other than the organic acid as
described above, as necessary.
It is also possible to add a polymer that traps copper ions (for example,
polyethyleneimine) after removing copper.
[0083] From the viewpoint of "3)" as described above, the second rinse may include a resin
decomposer that decomposes the semiconductor sealing composition. The resin decomposer
is not particularly limited as far as it is a compound that causes cleavage of carbon-carbon
bonds, carbon-nitrogen bonds or carbon-oxygen bonds in the resin, and a conventional
decomposer may be used. Specific examples of the resin decomposer include a compound
that generates radicals or ions such asW or OH-, such as hydrogen peroxide, nitric acid, and a
solution containing ozone; and hydrogen peroxide and,nitric acid are preferable.
[0084] The second rinse satisfies at least one of (A) the pH is 6 or lower, (B) the ionic
strength is 0.003 or more, or (C) a resin decomposer is included. The second rinse may
satisfy any two of (A) to (C), or may satisfy all of (A) to (C).
[0085] The second rinse preferably includes a solvent that has a high polarity and is less
likely to destroy a porous layer dielectric layer formed from silica or the like. This is
because the semiconductor sealing composition according to the invention has a high polarity
as described above, and therefore, the sealing composition readily dissolves in a solvent
having a high polarity, thereby improving the rinsing efficiency of the rinse. Specifically,
the solvent preferably includes a polar solvent such as water, methanol, ethanol, propanol,
butanol, or propylene glycol monomethyl ether acetate. ~
The second rinse may be applied with heat or ultrasonic waves.
[0086] The amounts of the solvent, acid, ioni'c compound and the like, which may be
incorporated in .the second rinse, can be adjusted as appropriate such that the pH and the ionic
strength of the second rinse each fall within the above ranges.
[0087] The second rinse can be prepared by mixing the solvent, acid, oxidant and the like.
In order to prevent contamination ofthe semiconductor circuit, it is preferable to prepare the
rinse under a clean environment such as in a clean room, or to remove, after the preparation of
the rinse, components that may contaminate the semiconductor circuit by means of
purification, filtration, or the like.
[0088] Th~ method of rinsing the back face of the semiconductor substrate according to the
23
-
invention is not particularly limited as far as the second rinse is used, and may be a generally
used method. Specifically, rinsing may be conducted by a back rinsing method in the
manufacture of a semiconductor, as described in lP-A No. 9-106980.
[0089]
In the semiconductor device production method of the present invention, the second
rinse may be used for rinsing the peripheral area ofthe front face of the semiconductor
substrate (the face on which at least the porous interlayer dielectric layer and the
semiconductor sealing layer are formed).
[0090] The term "peripheral area" refers to a portion on which a porous interlayer dielectric
layer or the like is not formed, which is usually an area of from approximately 1 to 10 mm in
width from the edge of the semiconductor substrate. Since a circuit formed on the peripheral
area ofthe semiconductor is difficult to take out by a dicing process or the like, the peripheral
area is usually disposed of after the dicing process. For this reason, a porous interlayer
dielectric layer is not formed on the surface ofthe peripheral area, and the semiconductor
substrate, whichis formed of silicon or a naturally oxidized film of silicon when silicon wafer
is used as the semiconductor substrate, is exposed at the peripheral area.
The semiconductor sealing layer formed on a surface of the peripheral area does not
exhibit a function of sealing the porous interlayer dielectric layer, as with the case of the
semiconductor sealing layer formed on the back face of the semiconductor substrate, and may
even cause contamination of the semiconductor circuit. Therefore, the semiconductor
sealing layer formed on a surface of the peripheral area is preferably removed by rinsing.
The rinsing of the peripheral area of the front surface of the semiconductor substrate
may be conducted by a generally used method of rinsing a peripheral area ofthe front surface
of a semiconductor substrate, provided that the second rinse is used, as with the case of
rinsing the back face of the semiconductor substrate as described above. ~ Specifically,
rinsing can be conducted by a so-called edge rinsing method in the manufacture of a
semiconductor, as described in lP-A No. 9-1 0~980.
The re£pective rinsing processes as described above may be carried out at the same
time, or may be carried out individually.
[0091]
The semiconductor device production method of the present invention may further
include, as necessary, processes that are usually performed, such as a wiring formation
process similar to that described above, after the sealing composition application process and
the rinsing process. For example, a copper wiring is formed by a known metal CVD method,
sputtering method, or electroplating method, followed by smoothening the film by CMP.
24
-
• Subsequently, a cap film is formed on the surface of the film. As necessary, a multilayer
wiring semiconductor device may be obtained by forming a hard mask and repeating the
sealing composition application process and the circuit face rinsing process.
[0092]
The semiconductor device production method ofthe invention may include a barrier
film (copper barrier layer) formation process, prior to the wiring formation process. By
forming a barrier film, diffusion of a metal component into the interlayer dielectric layer may
be suppressed more effectively.
The barrier film formation process can be carried out under the generally process
conditions. For example, a barrier film may be formed from a titanium compound such as
titanium nitride or a tantalum compound such as tantalum nitride, by the vapor phase growth
method (CVD), after the semiconductor sealing composition application process. In the
present invention, it is preferable to form a barrier film from a tantalum compound.
[0093]
The semiconductor device production method ofthe invention may include a
post-rinsing process in which the rinse remaining on the semiconductor substrate is removed,
after the circuit face rinsing process or the process of rinsing the back face of the
semiconductor substrate. The post-rinsing process can be performed by a generally used
method and is not particularly limited. Specifically, the rinsing can be conducted by a
post-rinsing method as described in lP-A No. 2008-47831. The rinse used in the
post-rinsing process (hereinafter, referred to as a "post-rinse") is not particularly limited as far
as it can remove the rinse by dissolving or decomposing the same. Specific examples
include a polar organic solvent such as and alcohol, water, a mixture of the polar organic
solvent and water, and a solution that includes an acid having degradability such as nitric acid
or sulfuric acid, or a solvent that includes ozone. "
[0094] 4. Semiconductor Device
The semiconductor device that is mariufactured by the method of the present
invention has a structure in which, for example, a porous interlayer dielectric layer, a resin
layer that includes a resin having a cationic functional group and a weight average molecular
weight of from 2,000 to 600,000 and has a thickness of from 0.3 run to 5 run, and a layer
formed from copper are positioned in this order. The semiconductor device may include
other layers, as necessary. By positioning the resin layer including a specific resin between
the interlayer dielectric layer and the wiring material, generation of a leak current or the like
can be suppressed and favorable characteristics can be achieved, even if the semiconductor
device has a fine circuit of 32 run or less.
25
-
• In the present invention, it is preferable that a copper barrier layer (preferably, a layer
formed from a tantalum compound) is further disposed between the resin layer and the wiring
material including copper.
EXAMPLES
[0095] Hereinafter, the present invention is specifically described with reference to the
Examples, but the scope of the present invention is not limited thereto.
[0096]
(Formation of Interlayer Dielectric layer)
A silicon wafer was coated with porous silica by dropping 1.0 mL of a composition
for forming porous silica onto a surface ofthe silicon wafer, and then rotating the silicon
wafer at 2,000 rpm for 60 seconds. The silicon wafer was then subjected to a heat treatment
under a nitrogen atmosphere at 150°C for 1 minute and at 350°C for 10 minutes. Thereafter,
the resulting substance was heated to 350°C in a chamber equipped with a 172 nm excimer
lamp, and was applied with ultraviolet rays for 10 minutes at a pressure of 1 Pa and an output
of 14 mW/cm2
• An interlayer dielectric layer (a porous silica film) was thus formed.
The density of the obtained interlayer dielectric layer was 0.887 g/cm3
.
Further, the obtained interlayer dielectric layer had a dielectric constant k of 2.0 and
an elastic modulus E of 6.60 GPa.
[0097] The density was measured in accordance with a conventional method, using an XRD
apparatus (TPR-IN-PLANE, manufactured by Rigaku Corporation) under the conditions of a..'1
X-ray source of 50 kV and 300 rnA, and a wavelength of 1.5418 A, within the scanning range
of from 0° to 1.5°.
The dielectric constant was measured in accordance with a conventional method,
using a mercury probe apparatus (SSM5130), under an atmosphere of 25'ilC and relative
humidity of 30%, at a frequency of 1 MHz.
The elastic modulus was measured in'accordance with a conventional method, using
a nanoindentate.r (TRIBOSCOPE, manufactured by Hysitron), with an indentation depth of
1/10 or less ofthe film thickness.
[0098] (Semiconductor Sealing Composition)
A composition obtained by dissolving 250 mg of polyethyleneimine (PEl,
manufactured by BASF Corporation; weight average molecular weight: 25,000, cationic
functional group equivalent weight: 309) in 100 mL of water was used as the semiconductor
sealing composition. The pH ofthe semiconductor sealing composition was 10.52. With
regard to the semiconductor sealing composition, the volume average particle diameter was
26
-
• measured in accordance with a dynamic light scattering method using ELSZ-2, manufactured
by Ootsuka Denshi Co., Ltd. The result was below the detection limit « 10 nm). The
measurement was conducted with a cumulative number of 70 and a number ofrepetition of 1.
The analysis was conducted by histogram analysis and cumulant analysis.
[0099] The content of sodium and the content of potassium in the semiconductor sealing
composition were measured with an ICP mass analyzer. The results were 10 ppb or less on
an elemental basis, respectively.
[0100] (Formation of Semiconductor Sealing Layer)
The semiconductor sealing composition (PEl aqueous solution) was brought into
contact with the interlayer dielectric layer (hereinafter, also referred to as "low-k") by a
spraying method (contact time with the solution: 20 seconds, spraying distance: 10 cm) with a
commercially available spray bottle "AIR-BOY" (manufactured by Carl Roth GmbH).
Subsequently, water was brought into contact by a spraying method (contact time with
ultrapure water: 10 seconds, spraying distance: 10 cm) using the same spray bottle. Then,
drying was conducted by air blowing, thereby forming a resin layer (semiconductor sealing
layer) on the interlayer dielectric layer. Thereafter, the following evaluation was performed
with regard to the sample (low-k/ PEl) that had been stored in an air-conditioned environment
of 23°C and 55% for at least 15 hours.
The water used herein was ultrapure water (MILL!-Q WATER, manufactured by
Millipore Corporation; resistivity of 18 MO·cm or less (at 25°C».
[0101] [Composition and Formation of Semiconductor Sealing Layer]
The element composition of the semiconductor sealing layer of the obtained sample
(low-k/ PEl) was measured with ESCALAB 220iXL (manufactured by VG) as an X-ray
photoelectron spectrometry (XPS) apparatus, under the conditions of an X-ray source ofAIKa
and an analysis region of
(Preparation of Rinse 1-1)
Rinse 1-1 was prepared by gradually adding oxalic acid dihydride (manufactured by
JUNSEI CHEMICAL CO., LTD.; special grade) to ultrapure water (MILLI-Q WATER,
manufactured by Millipore Corporation) while measuring the pH with a pH meter, and the pH
was adjusted to 3 at 25°C.
[0108] (Application of Sealing Composition)
A copper layer having a thickness of 50 nm was formed as a wiring material on a
surface of a silicon wafer (manufactured by Furuuchi Chemical Corporation; 8 inch, {I OO}
face, P-type, (boron doped), 10 to 20 ohm-cm, thickness: 700 to 775 llm) having an interlayer
dielectric layer on its surface, with a vacuum vapor deposition apparatus manufactured by
Showa Shinku Co., Ltd. (SGC-8) at a deposition rate of2 nm/sec for 25 seconds. A circuit
face provided with a porous interlayer dielectric layer and a wiring material including copper
was formed on one surface of a silicon wafer.
Th~ silicon wafer having the circuit face formed thereon was allowed to stand in air
28
-
for at least 2 hours, and a naturally oxidized film (copper oxide) was formed on the surface of
the wiring. Then, a portion having a wire on its surface was cut into a size of 5 mm square
and the surface was subjected to UV-03 treatment for 5 minutes. Onto this, 2 mL of the
semiconductor sealing composition (polyethyleneimine aqueous solution) of the
manufacturing example 1 was applied by dropping and spin casting at 600 rpm, thereby
forming a semiconductor sealing layer. Substrate 1 that includes a sealing layer/ a copper
layer/ a silicon layer was thus prepared.
[0109] (Rinsing of Circuit Face)
Next, the substrate 1 was immersed in the rinse 1 that fills a container having a
volume of 20 mL to a depth of 15 mm, and the container was placed on a shaker and
maintained for 60 minutes. Then, the container was emptied and the substrate 1 was rinsed
three times with ultrapure water. Subsequently, the substrate 1 was immersed in ultrapure
water that fills a container having a volume of 20 mL to a depth of 15 mm, and the container
was placed on a shaker and maintained for 15 minutes. The substrate 1 was taken out of the
container with apair of tweezers, rinsed for 1 minute with an ultrapure water wash bottle, and
dried by dry air blowing.
[0110] (Evaluation of Wire Rinsing)
With regard to the obtained sample, the element composition was measured with
ESCALAB 220iXL (manufactured by VG) as an XPS apparatus under the conditions of an
X-ray source ofAIKa and an analysis region of q>1 mm. Further, the sample was visually
observed in order to evaluate the wire rinsing. The element composition ofthe sample prim
to be washed with the rinse 1-1 was also measured in the same manner.
The amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer formed on the substrate 1
before the evaluation of wire rinsing was 8.9 atom%. However, after the evaluation of wire
rinsing, the color of copper oxide that appeared before rinsing was not recognized at all by
visual observation. Thus, it was confirmed ttat the rinse 1 exhibited an excellent rinsing
property with respect to the extra semiconductor sealing layer on the wire.
[0111] (Evaluation of Rinse Resistance)
In order to evaluate the rinse resistance of the sealing layer on the porous interlayer
dielectric layer, a silicon wafer (manufactured by Furuuchi Chemical Corporation; 8 inch,
{100} face, P-type, (boron doped), 10 to 20 ohm-em, thickness: 700 to 775 /lm) was allowed
to stand in air for at least 24 hours, thereby forming a naturally oxidized film on the surface.
The resultant was cut into a size of 5 mm square and the surface thereof was subjected to
UV-03 treatment for 5 minutes. Onto this, 2 mL ofthe semiconductor sealing composition
29
-
• (aqueous solution of polyethyleneimine) was applied by dropping and spin casting at 600 rpm,
whereby substrate 2 was prepared. The surface of the substrate 2 had a surface state of
porous silica, which is a kind of porous low-dielectric constant material.
[0112] Next, the substrate 2 was immersed in the rinse 1-1 that fills a container having a
volume of 20 mL to a depth of 15 mm, and the container was placed on a shaker and
maintained for 60 minutes. Then, the container was emptied and the substrate 2 was rinsed
three times with ultrapure water. Subsequently, the substrate 2 was immersed in ultrapure
water that fills a container having a volume of 20 mL to a depth of 15 mm, and the container
was placed on a shaker and maintained for 15 minutes. The substrate 2 was taken out of the
container with a pair of tweezers, rinsed for 1 minute with an ultrapure water wash bottle, and
dried by dry air blowing. The element composition was measured with ESCALAB 220iXL
(manufactured by VG) as an XPS apparatus under the conditions of an X-ray source ofAIKa
and an analysis region of
(Preparation of Rinse 1-2)
Rinse 2 was obtained by gradually adding oxalic acid dihydride (manufactured by
JUNSEI CHEMICAL CO., LTD.; special grade) to pure water (MILLI-Q WATER,
manufactured by Millipore Corporation) while measuring the pH with a pH meter to adjust
the pH to 5 at 25°C. "
[0115] Substrate 1 and substrate 2 were prepared and evaluation of wire rinsing and
evaluation of rinse resistance were conducted, 'in a manner substantially similar to that in
Example 1-1, except that the rinse 1-2 was used instead ofthe rinse 1-1.
The amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 1, before the
evaluation of wire rinsing was 8.9 atom%. However, after the evaluation of wire rinsing, the
color of copper oxide that appeared before the rinsing was not recognized at all by visual
observation. Thus, it was confirmed that the rinse 1-2 exhibited an excellent rinsing
property with respect to the extra semiconductor sealing layer on the wire.
Further, the amount (atom%) of nitrogen atoms, which represents the amount of
30
'.
• polyethyleneimine included in the semiconductor sealing layer on the substrate 2, before the
evaluation of rinse resistance was 9.3 atom%. However, after the evaluation of rinse
resistance, the amount was maintained to be 5.5 atom%. Thus, it was confirmed that the
semiconductor sealing layer on the porous low-dielectric constant material exhibited a
favorable rinse resistance with respect to the rinse 1-2.
[0116]
(Preparation of Rinse 1-3)
Rinse 1-3 was obtained by gradually adding 0.5 N aqueous ammonia to pure water
(MILLI-Q WATER, manufactured by Millipore Corporation) while measuring the pH with a
pH meter to adjust the pH to 7 at 25°C.
[0117] Substrate 1 and substrate 2 were prepared, and evaluation of wire rinsing and
evaluation or rinse resistance were conducted in a manner substantially similar to Example
1-1, except that the rinse 1-3 was used instead ofthe rinse 1-1.
The amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimirie included in the semiconductor sealing layer on the substrate 1, before the
evaluation of wire rinsing was 8.9 atom%. After the evaluation of wire rinsing, the amount
was decreased only to the amount of 4.7 atom%. Thus, it was confirmed that the rinsing
property of the rinse 1-3 with respect to the extra semiconductor sealing layer on the wire was
insufficient.
Further, the amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 2, before the.
evaluation of rinse resistance was 9.3 atom%. However, after the evaluation of rinse
resistance, the amount was decreased to 4.7 atom%. Thus, it was confirmed that the rinse
resistance of the semiconductor sealing layer on the porous low-dielectric constant material,
with respect to the rinse 1-3, was insufficient. ~
[0118]
(Preparation of Rinse 1-4)
Rinse 1-4 was obtained by gradually adding 0.5 N aqueous ammonia to pure water
(MILLI-Q WATER, manufactured by Millipore Corporation) while measuring the pH with a
pH meter to adjust the pH to 9 at 25°C.
[0119] Substrate 1 and substrate 2 were prepared, and evaluation of wire rinsing and
evaluation of rinse resistance were conducted in a manner substantially similar to Example
1-1, except that the rinse 1-4 was used instead of the rinse 1-1.
The amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 1, before the
31
-
.',
• evaluation of wire rinsing was 8.9 atom%. After the evaluation of wire rinsing, the amount
was decreased only to 6.6 atom%. Thus, it was confirmed that the rinsing property of the
rinse 1-4, with respect to the extra semiconductor sealing layer on the wire, was insufficient.
Further, the amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 2, before the
evaluation of rinse resistance was 9.3 atom%. However, after the evaluation of rinse
resistance, the amount was decreased to 3.9 atom%. Thus, it was confirmed that the rinse
resistance of the semiconductor sealing layer on the porous low-dielectric constant material,
with respect to the rinse 1-4, was insuffi.cient.
[0120]
(Preparation of Rinse 1-5)
Rinse 1-5 was obtained by gradually adding 0.5 N aqueous ammonia to pure water
(MILLI-Q WATER, manufactured by Millipore Corporation) while measuring the pH with a
pH meter to adjust the pH to 10.5 at 25°C.
[0121] Substrate 1 and thesubstrate 2 were prepared, and evaluation of wire rinsing and
evaluation of rinse resistance were conducted in a manner substantially similar to Example
1-1, except that the rinse 1-5 was used instead ofthe rinse 1-1.
The amount (atom%) of nitrogen atoms, which represents the ·amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 1, before the
evaluation of wire rinsing was 8.9 tom%. After the evaluation of wire rinsing, the amount
remained to be 8.9 atom%. Thus, it was confirmed that the rinsing property ofthe rinse 1-5;
with respect to the extra semiconductor sealing layer on the wire, was insufficient.
Further, the amount (atom%) of nitrogen atoms, which represents the amount of
polyethyleneimine included in the semiconductor sealing layer on the substrate 2, before the
evaluation of rinse resistance was 9.3 atom%. After the evaluation of rinse resistance, the
amount remained to be 9.3 atom%.
[0122]
(Synthesis of Rinse 2-1)
A 30% aqueous solution of hydrogen peroxide (manufactured by JUNSEI
CHEMICAL CO., LTD.; special grade) was used as rinse 2-1. The pH of the rinse 2-1 was
4.5 at 25°C.
[0123] (Preparation of Semiconductor Substrate)
In order to evaluate the back face rinsing and edge rinsing, a silicon wafer
(manufactured by Furuuchi Chemical Corporation; 8 inch, {100} face, P-type, (boron doped),
10 to 20 ohm-em, thickness: 700 to 775 !J.m) was allowed to stand in air for at least 24 hours,
32
-
thereby forming a naturally oxidized film on the surface. Then, the substrate was cut into a
size of 5 mm square and the surface thereof was subjected to UV-03 treatment for 5 minutes.
Onto this, 2 mL of the semiconductor sealing composition (aqueous solution of
polyethyleneimine) was applied by dropping and spin casting at 600 rpm, thereby forming a
semiconductor sealing phase. A silicon wafer was thus prepared.
[0124] (Evaluation ofEBR Characteristics)
Next, the silicon wafer prepared above was immersed in the rinse 2-1 in a container
having a volume of 20 mL to a depth of 15 mm, and the container was placed on a shaker and
maintained for 60 minutes. Then, the container was emptied and the silicon wafer was
rinsed three times with ultrapure water. Subsequently, the silicon wafer was immersed in
ultrapure water that fills a container having a volume of 20 mL to a depth of 15 mm, and the
container was placed on a shaker and maintained for 15 minutes. The silicon wafer was
taken out of the container with a pair of tweezers, rinsed for 1 minute with an ultrapure water
wash bottle, and dried by dry air blowing. The element composition was measured with
ESCALAB 220iXL (manufactured by VO) as an XPS apparatus under the conditions of an
X-ray source ofA1Ka and an analysis region of
(Synthesis of Rinse 2-2)
Rinse 2-2 having an ionic strength of 0.005 was obtained by adding oxalic acid
dihydride (manufactured by JUNSEI CHEMICAL CO., LTD.; special grade) to ultrapure
water, while measuring the pH with a pH met~r to adjust to 2.0 ± 0.05 at 25°C.
[0127] Preparation of a semiconductor substrate and evaluation ofEBR characteristics were
conducted in a manner substantially similar to Example 2-1, except that the rinse 2-2 was
used instead ofthe rinse 2-1. The amount (atom%) of nitrogen atoms, which represents the
amount of polyethyleneimine included in the semiconductor sealing layer on the
semiconductor substrate, before the evaluation ofEBR was 8 atom%. However, after the
evaluation of EBR, the amount was decreased to 2.1 atom%. Thus, it was confirmed that the
rinse 2-2 exhibited a favorable rinsing property with respect to the semiconductor sealing
layer.
33
-
"
• [0128]
(Synthesis of Rinse 2-3)
Rinse 2-3 having an ionic strength of 0.0039 was obtained by adding hydrochloric
acid to ultrapure water, while measuring the pH with a pH meter to adjust to 2.0 ± 0.05 at
25°C.
[0129] Preparation of a semiconductor substrate and evaluation ofEBR characteristics were
conducted in a manner substantially similar to Example 2-1, except that the rinse 2-3 was
used instead of the rinse 2-1. The amount (atom%) of nitrogen atoms, which represents the
amount of polyethyleneimine included in the semiconductor sealing layer on the
semiconductor substrate, before the evaluation ofEBR was 8 atom%. However, after the
evaluation ofEBR, the amount was decreased to 3.73 atom%. Thus, it was confirmed that
the rinse 2-2 exhibited a favorable rinsing property with respect to the semiconductor sealing
layer.
[0130]
(Synthesis of Rinse 2-4)
Rinse 2-4 having an ionic strength of 0.0055 was obtained by adding
methanesu1fonic acid to ultrapure water, while measuring the pH with a pH meter to adjust to
2.0 ± 0.05 at 25°C.
[0131] Preparation of a semiconductor substrate and evaluation ofEBR characteristics were
conducted in a manner substantially similar to Example 2-1, except that the rinse 2-4 was
used instead of the rinse 2-1. The amount (atom%) ofnitrogen atoms, which represents the.
amount of polyethyleneimine included in the semiconductor sealing layer on the
semiconductor substrate, before the evaluation ofEBR was 8 atom%. However, after the
evaluation of EBR, the amount was decreased to 1.77 atom%. Thus, it was confirmed that
the rinse 2-4 exhibited a favorable rinsing property with respect to the semiconductor sealing
layer.
[0132]
(Synthesis of Rinse 2-5)
Rinse 2-5 having an ionic strength of 0.0071 was obtained by adding nitric acid to
ultrapure water while measuring the pH with a pH meter to adjust to 2.0 ± 0.05 at 25°C.
[0133] Preparation of a semiconductor substrate and evaluation ofEBR characteristics were
conducted in a manner substantially similar to Example 2-1, except that the rinse 2-5 was
used instead ofthe rinse 2-1. The amount (atom%) ofnitrogen atoms, which represents the
amount of polyethyleneimine included in the semiconductor sealing layer on the
semiconduktor substrate, before the evaluation ofEBR was 8 atom%. However, after the
34
-
• evaluation ofEBR, the amount was decreased to 3.44 atom%. Thus, it was confirmed that
the rinse 2-5 exhibited a favorable rinsing property with respect to the semiconductor sealing
layer.
[0134]
(Synthesis of Rinse 2-6)
Ultrapure water was used as rinse 2-6. The pH of the rinse 2-6 was from 6.5 to 7.0
at 25°C, and the ionic strength was O.
[0135] Preparation of a semiconductor substrate and evaluation ofEBR characteristics were
conducted in a manner substantially similar to that in Example 2-1, except that the rinse 2-6
was used instead of the rinse 2-1. The amount (atom%) of nitrogen atoms, which represents
the amount of polyethyleneimine included in the semiconductor sealing layer on the
semiconductor substrate, before the evaluation ofEBR was 8 atom%. However, after the
evaluation ofEBR, the amount was decreased only to 5.9 atom%. Thus, it was confirmed
that the rinse 2-6 did not exhibit a favorable rinsing property with respect to the
semiconductor sealing layer.
",
35

• CLAIMS
1. A semiconductor device production method, the method comprising:
a sealing composition application process in which a semiconductor sealing layer is
formed by applying, to at least a portion of a surface of a semiconductor substrate, a
semiconductor sealing composition that includes a resin having a cationic functional group
and a weight average molecular weight of from 2,000 to 600,000, wherein a content of
sodium and a content of potassium are 10 mass ppb or less on an elemental basis,
respectively; and, subsequently,
a rinsing process in which the surface of the semiconductor substrate on which the
semiconductor sealing layer has been formed is rinsed with a rinse having a pH at 25°C of 6
or lower.
2. The semiconductor device production method according to claim 1, wherein the
resin having a cationic functional group and a weight average molecular weight of from 2,000
to 600,000 has a cationic functional group equivalent amount of from 43 to 430.
3. The semiconductor device production method according to Claim 1, wherein the
resin having a cationic functional group and a weight averagemolecular weight of from 2,000
to 600,000 is polyethyleneimine or a polyethyleneimine derivative.
4. The semiconductor device production method according to claim 1, wherein a
porous interlayer dielectric layer is formed on at least a portion of the surface of the
semiconductor substrate.
5. The semiconductor device production method according to claim 4, wherein the
semiconductor sealing layer is formed on the porous interlayer dielectric layer, the porous
interlayer dielectric layer has a concave groove having a width of from 10 nm to 32 nm, and
the sealing composition application process includes contacting the semiconductor sealing
composition to at least a side face ofthe concave groove of the porous interlayer dielectric
layer.
6. The semiconductor device production method according to claim 4, wherein the
porous interlayer dielectric layer contains porous silica, and has a silanol residue derived from
the porous .silica on a surface ofthe porous interlayer dielectric layer.
36
-
7. The semiconductor device production method according to claim 1, wherein the
rinse includes at least one solvent selected from the group consisting of water, methanol,
ethanol, propanol, butanol and propylene glycol monomethyl ether acetate.
8. The semiconductor device production method according to claim 1, wherein the
rinse includes at least one acid selected from the group consisting of oxalic acid, formic acid,
citric acid, p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid and nitric acid.
9. The semiconductor device production method according to claim 1, wherein the
surface of the semiconductor substrate on which the semiconductor sealing layer has been
formed comprises a surface on which a semiconductor circuit is not formed.
10. The semiconductor device production method according to claim 9, wherein the
rinse, with which the surface on which a semiconductor circuit is not formed is rinsed, has a
pH at 25°C of2 or lower.
11. The semiconductor device production method according to claim 1, wherein at
least a portion of the surface of the semiconductor substrate comprises a circuit face that is
provided with a porous interlayer dielectric layer and a wiring material that includes copper,
and the rinsing process is a circuit face rinsing process in which the sealing layer on the
wiring material is removed.
12. The semiconductor device production method according to claim 11, wherein the
rinse with which the semiconductor circuit face is rinsed has a pH at 25°<;: of 1 or higher.
13. A rinse for removing a semiconduCtor sealing layer that is derived from a resin
having a cationic functional group and a weight average molecular weight of from 2,000 to
600,000, the semiconductor sealing layer being positioned on a metal wiring of a
semiconductor circuit face or on a semiconductor substrate, and the rinse having a pH at 25°C
of 6 or lower.
14. The rinse according to claim 13, wherein the resin having a cationic functional
group and a weight average molecular weight of from 2,000 to 600,000 has a cationic
functional group equivalent amount of from 43 to 430, and the cationic functional group is at
37
-
~ least one selected from the group consisting of a primary amino group and a secondary amino
group. ..
15. The rinse according to claim 13, wherein the rinse has a pH at 25°C of 1 or
higher and is used for rinsing the semiconductor circuit face.
16. The rinse according to claim 13, wherein the rinse has a pH at 25°C of2 or lower
and is used for rinsing a face of the semiconductor substrate on which the circuit is not
formed.
Dated this 25/2/2013
~~~~~.
OF REMFRY & SAGAR
ATTORNEY FOR THE APPLICANT
",
38