FORMING A SUBSTRATE WEB TRACK IN AN ATOMIC LAYER
DEPOSITION REACTOR
FIELD OF THE INVENTION
The present invention generally relates to deposition reactors. More particularly,
the invention relates to providing a substrate web track with a repeating pattern
into a reaction vessel in a deposition reactor.
BACKGROUND OF THE INVENTION
Atomic Layer Epitaxy (ALE) method was invented by Dr. Tuomo Suntola in the
early 1970's. Another generic name for the method is Atomic Layer Deposition
(ALD) and it is nowadays used instead of ALE. ALD is a special chemical
deposition method based on the sequential introduction of at least two reactive
precursor species to at least one substrate.
Thin films grown by ALD are dense, pinhole free and have uniform thickness. For
example, in an experiment aluminum oxide has been grown by thermal ALD from
trimethylaluminum (CH3)3AI, also referred to as TMA, and water resulting in only
about 1% non-uniformity over a substrate wafer.
One interesting application of ALD technique is to provide coatings on a moving
substrate web.
SUMMARY
According to a first example aspect of the invention there is provided a method
comprising:
forming a substrate web track with a repeating pattern into a reaction vessel of an
atomic layer deposition reactor by moving a first set of support rolls in relation to a
second set of support rolls; and
supporting the substrate web by the first and second sets of support rolls when the
track has been formed.
In certain example embodiments, the reaction vessel is a reaction chamber. In
certain example embodiments, the reaction chamber is surrounded by a vacuum
chamber (the vacuum chamber houses the reaction chamber). In certain example
embodiments, the reaction vessel is a reaction chamber inside an in-line atomic
layer deposition module.
In certain example embodiments, the method comprises moving the first set of
support rolls from a first side of the second set of support rolls to the other side of
the second set of support rolls. By the term roll is here meant both ordinary rolls
and wheels as well as other equivalent mechanical means for turning and
supporting a substrate web.
In certain example embodiments, the method comprises forming inside the
reaction vessel a three-dimensional atomic layer deposition flow volume defined
by a reaction vessel lid, reaction vessel sidewalls and the formed substrate web
track. In this way, the area of surfaces that need cleaning after processing can be
reduced, being in an example embodiment basically only the reaction vessel
sidewalls and lid.
The deposition reactor may be an ALD reactor. In certain example embodiments,
the deposition reactor comprises a reaction chamber providing a reaction space.
The reaction chamber can be closed by a lid. In certain example embodiments, the
first set of support rolls is attached to a chamber lid. The first set of support rolls
can be attached to the chamber lid, for example, by at least one support stem. The
at least one support stem can be stationary or deformable. The movement of the
first set of rolls can be effected, for example, by deforming the at least one stem
(the at least one stem can have a nested structure or similar), by moving the at
least one stem via a feedthrough arranged in the chamber lid, or the movement
can be effected by a movement of the chamber lid itself.
In certain example embodiments, precursor vapor is fed into the reaction chamber
(or vessel) through the reaction chamber (or vessel) lid.
In certain example embodiments, the reaction chamber is surrounded by a
vacuum chamber. In certain example embodiments, inactive gas is fed into the
vacuum chamber to obtain an overpressure in relation to the reaction chamber.
The reactor in certain example embodiments comprises an inactive gas in-feed
line into the vacuum chamber.
In certain example embodiments, the first set of support rolls are attached to a
counterpart in a roof or wall of a reaction chamber, or alternatively in a roof or wall
of a reaction unit or module forming the reaction space. Depending on the
implementation, the reaction unit or module can reside within a reaction chamber.
The movement of the first set of rolls can be effected, for example, by moving the
counterpart in the roof or wall to which the first set of support rolls is attached. The
movement can be driven by an actuator external to the reaction chamber, or
external to the reaction space.
In certain example embodiments, the substrate web is loaded into the reaction
chamber from the top of the reaction chamber supported by the first set of rolls.
In certain example embodiments, the method comprises forming a track of a
pleated form by pushing the substrate web by the first set of support rolls to the
other side of the second set of the support rolls. The movement of the first set of
rolls may be translational motion.
In certain example embodiments, the method comprises removing gases from the
reaction space, during deposition, via a route travelling through the first set of
support rolls.
The rolls of the first set of rolls may be partially open at the ends and on the sides
of the rolls. The rolls may have a roll axis that is thinner than the outer diameter of
the rolls. The rolls may be implemented by wheels that are spatially separated
from each other. They may have a common rotation axis formed by the roll axis.
In certain example embodiments, a substrate web source roll is integrated into a
chamber lid of the deposition reactor. The chamber lid is a movable lid. The
substrate web source roll may be integrated on the other side of the lid compared
to the side on which the reaction space resides.
In certain example embodiments, the substrate web is fed into a reaction chamber
or reaction space through a chamber lid.
The chamber lid mentioned may be a lid closing the reaction chamber. The lid is
may be dual-lid system comprising a reaction chamber lid integrated to a vacuum
chamber lid.
According to a second example aspect of the invention there is provided an atomic
layer deposition reactor, comprising:
a reaction vessel configured to provide a reaction space;
a first set of support rolls; and
a second set of support rolls, wherein
the first and second sets of support rolls are configured to form a substrate web
track with a repeating pattern into the reaction vessel by moving the first set of
support rolls in relation to the second set of support rolls; and the first and second
sets of support rolls are configured to support the substrate web when the track
has been formed.
The reaction space is the volume in which the deposition reactions of the
deposition reactor occur. The reaction chamber may practically be the same
volume as the reaction space or the reaction chamber may be configured to
provide the reaction space within the reaction chamber by defining a smaller
volume within the reaction chamber or by accommodating a smaller unit or module
(reaction vessel) within the reaction chamber.
In certain example embodiments, the deposition reactor comprises a mechanism
configured to move the first set of support rolls from a first side of the second set
of support rolls to the other side of the second set of support rolls.
In certain example embodiments, the first and second sets of support rolls are
configured to form a track of a pleated form by pushing the substrate web by the
first set of support rolls to the other side of the second set of the support rolls.
In certain example embodiments, the deposition reactor is configured to remove
gases from the reaction space, during deposition, via a route travelling through the
first set of support rolls.
In certain example embodiments, the deposition reactor is configured to form
inside the reaction vessel a three-dimensional atomic layer deposition flow volume
defined by a reaction vessel lid, reaction vessel sidewalls and the formed
substrate web track.
In certain example embodiments, a substrate web source roll is integrated into a
chamber lid of the deposition reactor.
In certain example embodiments, a chamber lid of the deposition reactor
comprises a feedthrough configured feed the substrate web into the reaction
chamber or reaction space through the chamber lid.
In certain example embodiments, the reaction chamber lid (or vessel lid)
comprises a channel configured to feed precursor vapor into the reaction chamber
(or vessel) through the reaction chamber lid (or vessel lid).
Different non-binding example aspects and embodiments of the present invention
have been illustrated in the foregoing. The above embodiments are used merely to
explain selected aspects or steps that may be utilized in implementations of the
present invention. Some embodiments may be presented only with reference to
certain example aspects of the invention. It should be appreciated that
corresponding embodiments may apply to other example aspects as well. Any
appropriate combinations of the embodiments may be formed.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to the
accompanying drawings, in which:
Figs. 1 and 2 show a schematic view of a deposition reactor and automatic
forming of a substrate web track in the deposition reactor in
accordance with an example embodiment,
Fig. 3 shows a structure of a support roll in accordance with an
example embodiment, and
Figs. 4 and 5 show a schematic view of a module for forming a reaction space
and automatic forming of a substrate web track in the module in
accordance with an example embodiment.
DETAILED DESCRIPTION
In the following description, Atomic Layer Deposition (ALD) technology is used as
an example. The basics of an ALD growth mechanism are known to a skilled
person. As mentioned in the introductory portion of this patent application, ALD is
a special chemical deposition method based on the sequential introduction of at
least two reactive precursor species to at least one substrate. The at least one
substrate is exposed to temporally separated precursor pulses in the reaction
chamber to deposit material on the substrate surfaces by sequential self-saturating
surface reactions. In the context of this application, the term ALD comprises all
applicable ALD based techniques and any equivalent or closely related
technologies, such as, for example MLD (Molecular Layer Deposition) and PEALD
(Plasma Enhanced Atomic Layer Deposition) techniques.
A basic ALD deposition cycle consists of four sequential steps: pulse A, purge A,
pulse B and purge B. Pulse A consists of a first precursor vapor and pulse B of
another precursor vapor. Inactive gas and a vacuum pump are typically used for
purging gaseous reaction by-products and the residual reactant molecules from
the reaction space during purge A and purge B. A deposition sequence comprises
at least one deposition cycle. Deposition cycles are repeated until the deposition
sequence has produced a thin film or coating of desired thickness. Deposition
cycles can also be more complex. For example, the cycles can include three or
more reactant vapor pulses separated by purging steps. All these deposition
cycles form a timed deposition sequence that is controlled by a logic unit or a
microprocessor.
In certain example embodiments as described in the following, there is provided a
method and apparatus for forming a substrate web track with a repeating pattern
into a reaction space of a deposition reactor. Fig. 1 shows such a deposition
reactor (deposition reactor 10). The deposition reactor 10 comprises a vacuum
chamber wall 4 1 forming a vacuum chamber 45. Within the vacuum chamber 45,
and surrounded by the vacuum chamber 45, the deposition reactor 10 comprises a
reaction chamber (or vessel) 44. The reaction chamber 44 is defined by a reaction
chamber wall 42. The vacuum chamber 45 and the reaction chamber 44 are
closed by a chamber lid, which in Fig. 1 is in its upper position (i.e., initial position
for loading a substrate web). In the example shown in Fig. 1 the chamber lid is a
dual-lid system comprising a vacuum chamber lid 2 1 that is integrated with a
reaction chamber lid 22.
In the embodiment shown in Fig. 1, a substrate web 15 is loaded into the reaction
chamber 44 from the top side of the reaction chamber 44. A substrate web source
roll 11 is integrated to the chamber lid. In the event of the dual-lid system, the
source roll 11 is integrated either to the reaction chamber lid 22 or, as shown in
Fig. 1, to the vacuum chamber lid 2 1. The substrate web source roll 11 may then
reside on the other side of the chamber lid (or respective lid) than the reaction
chamber 44. The substrate web source roll 11 may reside in a housing 13
integrated to the chamber lid (or respective lid).
The chamber lid comprises a feedthrough through which the substrate web 15 on
the source roll 11 travels from one side of the lid to the other side of the lid. In the
event the chamber lid is a dual-lid system, there may be a feedthrough through
both lids 2 1 and 22 depending on the implementation. On the reaction chamber
side of the chamber lid, the route of the substrate web extends substantially
vertically downwards. The vertically extending route turns at a first edge roll 17 of
a first set of support rolls. The route continues in a substantially horizontal
direction passing a center roll 27 of the first set of support rolls (in other
embodiments, there may be zero or more than one center/intermediate roll). The
horizontally extending route, in turn, turns at a second edge roll 37 of the first set
of support rolls upwards, and extends substantially vertically upwards until it
reaches the chamber lid.
A substrate web destination roll 12 is integrated to the chamber lid. In the event of
the dual-lid system, the destination roll 12 is integrated either to the reaction
chamber lid 22 or, as shown in Fig. 1, to the vacuum chamber lid 2 1. The
substrate web destination roll 12 may then reside on the other side of the chamber
lid (or respective lid) than the reaction chamber 44. The substrate web destination
roll 12 may reside in a housing 14 integrated to the chamber lid (or respective lid).
Inactive gas may be fed into the housing 14 as well as housing 13 during
deposition.
The chamber lid comprises a feedthrough through which the substrate web 15
travels from one side of the lid to the other side of the lid and is finally wound up
onto the destination roll 12 . In the event the chamber lid is a dual-lid system, there
may be a feedthrough through both lids 2 1 and 22 depending on the
implementation.
The first set of support rolls are integrated to the chamber lid by respective support
stems 16, 26 and 36. There may be one or more support stems depending on the
implementation.
In the event of the dual-lid system, the at least one support stem may be attached
to the reaction chamber lid 22. Alternatively, the at least one support stem may be
attached to the vacuum chamber lid 2 1, or to both lids. In yet an alternative, the at
least one support stem may merely go through the reaction chamber lid 22 at a
feedthrough and be attached to the vacuum chamber lid 2 1. In yet an alternative,
the at least one support stem go through the whole chamber lid or lid system by
feedtrough(s), and is attached to a support point on the outside of the reaction
chamber or on the outside of the vacuum chamber. In all of these embodiments,
the at least one support stem or similar is considered to be integrated to the
chamber lid (or to the reaction chamber lid).
The deposition reactor 10 comprises a second set of support rolls in the reaction
chamber 44. The rolls of the second set may be rotatable mounted, for example,
to the reaction chamber wall 42. The rolls of the second set of support rolls can
consist of at least one roll. Preferable, the second set of support rolls comprises at
least two rolls. If there are more than two rolls, then the second set comprises both
edge rolls and intermediate rolls. In Fig. 1 there are shown a first edge roll 18 and
a second edge roll 28 of the second set of support rolls. As mentioned, there may
be one or more intermediate rolls depending on the implementation. The second
set of support rolls may be placed on a row, i.e., the rolls of the second set may be
placed on the same level with respect to the other rolls belonging to the second
set.
The deposition reactor 10 is a reactor that is loadable from the top side of the
reactor. The deposition reactor comprises the chamber lid on the top side of the
reaction chamber 44 and an exhaust line 43 at the bottom side of the reaction
chamber 44. The deposition reactor 10 further comprises the required precursor
vapor in-feed lines and purge gas in-feed lines (denoted by reference numerals 46
and 47 in Fig. 1) for feeding precursor vapor and purge gas into the reaction
chamber 44 in accordance with ALD technology. The precursor vapor may be fed
into the reaction chamber through the reaction chamber lid 22.
A substrate web track with a repeating pattern as shown in Fig. 2 is formed by
moving the first set of support rolls in relation to the second set of support rolls. In
practice this can be achieved, for example, by lowering the chamber lid from its
upper (initial) position into its lower position. The first set of support rolls 17-37
moving from a first side (here: upper side) of the second set of support rolls 18-28
to the other side (here: lower side) of the second set of support rolls cause the
desired track formation. In the end position as shown in Fig. 2 the substrate web is
supported by both the first and second sets of support rolls and a track of a
pleated form has been formed. The rolls that in the initial state form upper rolls
(i.e., the first set of support rolls) become by the track formation the lower rolls as
shown in Fig. 2 .
The first set of support rolls can be moved by a mechanism, such as the at least
one support stem shown in Figs. 1 and 2 . The at least one support stem can be
stationary or deformable with respect to the chamber lid. The movement of the first
set of rolls can be effected, for example, by a movement of the chamber lid itself
(as shown in Figs. 1 and 2). Alternatively, or in addition, the movement of the first
set of rolls can be effected, for example, by deforming the at least one stem (the at
least one stem can have a nested structure or similar) and/or by moving the at
least one stem via a feedthrough arranged in the chamber lid (or reaction chamber
lid).
The in-feed lines 46 and 47 in the embodiment shown in Fig. 1 travel through the
vacuum chamber wall 4 1 and face the reaction chamber 44 at its top section. In
the example embodiment of Fig. 1, the precursor vapor and purge gas enter the
reaction chamber 44 from the top. They may flow through the reaction chamber lid
22. The pleated form of the track together with the reaction chamber (side) wall 42
and the reaction chamber lid 22 form a partially closed space, the reaction space.
The side of the substrate web facing the reaction space is coated by sequential
self-saturating surface reactions in accordance with the ALD technology. The
arrows drawn within the reaction space in Fig. 2 show the direction of flow within
the reaction space. The precursor vapor and purge gas flow as a top-to-bottom
flow along the substrate web surface in pockets of the pleated form.
In certain example embodiments, the method comprises removing gases from the
reaction space, during deposition, via a route travelling through the first set of
support rolls. The rolls 17-37of the first set of rolls may be partially open at the
ends and on the sides of the rolls. The gases exit the reaction space via the open
ends of the rolls 17-37 to the exhaust line 43 as shown by the arrows in Fig. 2 .
Fig. 3 shows the structure of a roll (for example, roll 17) belonging to the first set of
support rolls in accordance with an example embodiment. The roll 17 comprises
wheels 5 1, 52 and 53 which are connected to a common roll axis 54 by a set of
spokes 56 or similar. The roll axis 54 is thinner than the diameter of the wheels 5 1-
53. The roll 17 is open on the side of the roll and at the ends of the roll. The roll
may optionally comprise a perforated mantle 55 around it. The structure of the roll
17 is thereby such that it allows gases to flow through it and to exit via its ends.
Figs. 4 and 5 show a schematic view of an ALD module 70 designed for an in-line
solution, i.e., for forming a part of a production line. The module 70 of comprises
an input slot and an output slot for a substrate web 65 at its opposite sides. A
reaction chamber (vessel) is formed by a body part 72 and a lid part (or roof) 7 1
within the module 70. The lid part 7 1 is vertically movable by support stems 6 1 and
62 that are attached thereto. The support stems 6 1 and 62 extend through the roof
of the module 70 at feedthroughs 63 and 64, respectively. The vertical movement
can be driven by an external actuator (not shown).
The module 70 comprises a first set of substrate web support rolls 66 and a
second set of substrate web support rolls 67 similarly as described in the foregoing
embodiments. A general reference is made to the foregoing embodiments as to
the structure and operation of the support rolls. The second set of rolls 67 is
stationary while the first set of rolls 66 can be moved. A movement mechanism 68
for moving the first set of rolls 66 is attached to the reaction chamber wall (as
shown in Fig. 4). The movement mechanism 68 may also be connected to the
reaction chamber lid part 7 1 so that when the reaction chamber lid part 7 1 is
moved vertically by the external actuator, the first set of rolls 66 move together
with it.
A substrate web track with a repeating pattern as shown in Fig. 5 is formed by
moving the first set of support rolls 66 in relation to the second set of support rolls
67. This is, again, achieved by lowering the chamber lid part 7 1 from its upper
(initial) position into its lower position. The first set of support rolls 66 moving from
an upper side of the second set of support rolls 67 to the lower side of the second
set of support rolls cause the desired track formation. In the end position as shown
in Fig. 5 the substrate web is supported by both the first and second sets of
support rolls and a track of a pleated form has been formed.
The reaction chamber further comprises an apertures 69 at the point to which the
first set of support rolls 66 move by the vertical movement so that gases can exit
via the ends of first set of support rolls 66 similarly as in the foregoing
embodiments.
The precursor vapor may be fed into the reaction vessel from the top through (one
or more channels in) the reaction vessel lid part 7 1. In certain example
embodiments, the precursor vapor is fed via a channel formed inside at least one
support stem 6 1 and/or 62. The module forms inside the reaction vessel a threedimensional
atomic layer deposition flow volume defined by the reaction vessel lid
part 7 1, reaction vessel sidewalls and the formed substrate web track.
Without limiting the scope and interpretation of the patent claims, certain technical
effects of one or more of the example embodiments disclosed herein are listed in
the following: A technical effect is automatic track formation by moving a first set of
support rolls in relation to a second set of support rolls. Another technical effect is
achieving a top-to-bottom flow by removing gases from the reaction space via a
route travelling through the first (i.e., lower) set of support rolls.
It should be noted the some of the functions or method steps discussed in the
preceding may be performed in a different order and/or concurrently with each
other. Furthermore, one or more of the above-described functions or method steps
may be optional or may be combined.
The foregoing description has provided by way of non-limiting examples of
particular implementations and embodiments of the invention a full and informative
description of the best mode presently contemplated by the inventors for carrying
out the invention. It is however clear to a person skilled in the art that the invention
is not restricted to details of the embodiments presented above, but that it can be
implemented in other embodiments using equivalent means without deviating from
the characteristics of the invention.
Furthermore, some of the features of the above-disclosed embodiments of this
invention may be used to advantage without the corresponding use of other
features. As such, the foregoing description should be considered as merely
illustrative of the principles of the present invention, and not in limitation thereof.
Hence, the scope of the invention is only restricted by the appended patent claims.

Claims
1. A method comprising:
forming a substrate web track with a repeating pattern into a reaction vessel
of an atomic layer deposition reactor by moving a first set of support rolls in
relation to a second set of support rolls; and
supporting the substrate web by the first and second sets of support rolls
when the track has been formed.
2 . The method of claim 1, comprising moving the first set of support rolls from a
first side of the second set of support rolls to the other side of the second set
of support rolls.
3 . The method of claim 2, comprising forming a track of a pleated form by
pushing the substrate web by the first set of support rolls to the other side of
the second set of the support rolls.
4 . The method of any preceding claim, comprising forming inside the reaction
vessel a three-dimensional atomic layer deposition flow volume defined by a
reaction vessel lid, reaction vessel sidewalls and the formed substrate web
track.
5 . The method of any preceding claim, comprising removing gases from the
reaction space, during deposition, via a route travelling through the first set of
support rolls.
6 . The method of any preceding claim, wherein a substrate web source roll is
integrated into a chamber lid of the deposition reactor.
7 . The method of any preceding claim, wherein the substrate web is fed into a
reaction chamber or reaction space through a reaction chamber lid.
8 . An atomic layer deposition reactor, comprising:
a reaction vessel configured to provide a reaction space;
a first set of support rolls; and
a second set of support rolls, wherein
the first and second sets of support rolls are configured to form a substrate
web track with a repeating pattern into the reaction vessel by moving the first
set of support rolls in relation to the second set of support rolls; and the first
and second sets of support rolls are configured to support the substrate web
when the track has been formed.
9 . The deposition reactor of claim 8, comprising a mechanism configured to
move the first set of support rolls from a first side of the second set of support
rolls to the other side of the second set of support rolls.
10 . The deposition reactor of claim 8, wherein the first and second sets of support
rolls are configured to form a track of a pleated form by pushing the substrate
web by the first set of support rolls to the other side of the second set of the
support rolls.
11. The deposition reactor of any preceding claim 8-1 0, wherein deposition reactor
is configured to remove gases from the reaction space, during deposition, via
a route travelling through the first set of support rolls.
12 . The deposition reactor of any preceding claim 8-1 1, wherein a substrate web
source roll is integrated into a chamber lid of the deposition reactor.
13 . The deposition reactor of any preceding claim 8-1 2, wherein a chamber lid of
the deposition reactor comprises a feedthrough configured to feed the
substrate web into the reaction chamber or reaction space through the
chamber lid.