U.S. patent number RE46,390 [Application Number 14/687,304] was granted by the patent office on 2017-05-02 for pattern forming method, processing method, and processing apparatus.
This patent grant is currently assigned to Kabushiki Kaisha Toshiba. The grantee listed for this patent is KABUSHIKI KAISHA TOSHIBA. Invention is credited to Masafumi Asano, Masayuki Hatano, Ryoichi Inanami.
United States Patent |
RE46,390 |
Asano , et al. |
May 2, 2017 |
Pattern forming method, processing method, and processing
apparatus
Abstract
According to the embodiments, a distribution of a recess portion
shape is calculated based on a result obtained by measuring the
recess portion shape of a first projection and recess pattern
formed on a surface of a template. Next, a distribution of an
application amount of a curing agent to a processing target layer
is calculated based on the distribution of the recess portion
shape, and the curing agent is applied to the processing target
layer based on this distribution of the application amount of the
curing agent. Next, a second projection and recess pattern is
formed by transferring the first projection and recess pattern onto
the curing agent by causing the curing agent to cure in a state
where the first projection and recess pattern is in contact with
the curing agent.
Inventors: |
Asano; Masafumi (Kanagawa,
JP), Inanami; Ryoichi (Kanagawa, JP),
Hatano; Masayuki (Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOSHIBA |
Minato-ku, Tokyo |
N/A |
JP |
|
|
Assignee: |
Kabushiki Kaisha Toshiba
(Tokyo, JP)
|
Family
ID: |
1000001945549 |
Appl.
No.: |
14/687,304 |
Filed: |
April 15, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
13041917 |
Mar 7, 2011 |
8420422 |
Apr 16, 2013 |
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Foreign Application Priority Data
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Mar 19, 2010 [JP] |
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2010-064916 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
22/20 (20130101); B82Y 40/00 (20130101); H01L
22/12 (20130101); G03F 7/0002 (20130101); B82Y
10/00 (20130101); H01L 22/20 (20130101); H01L
22/12 (20130101); B82Y 10/00 (20130101); G03F
7/0002 (20130101); B82Y 40/00 (20130101) |
Current International
Class: |
H01L
21/00 (20060101); H01L 21/66 (20060101); B82Y
40/00 (20110101); G03F 7/00 (20060101); B82Y
10/00 (20110101) |
Field of
Search: |
;438/14
;257/E21.525 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2006-140382 |
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Jun 2006 |
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JP |
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2007-296783 |
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Nov 2007 |
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JP |
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2008-126450 |
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Jun 2008 |
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JP |
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WO 2009/153926 |
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Dec 2009 |
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WO |
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Other References
Notice of Rejection mailed by the Japanese Patent Office on Jun.
19, 2012, for Japanese Patent Application No. 2010-064916, and
English-language translation thereof. cited by applicant.
|
Primary Examiner: Menefee; James
Attorney, Agent or Firm: Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP
Claims
What is claimed is:
1. A processing method comprising: measuring a recess portion shape
of a first projection and recess pattern formed on a surface of a
template; calculating a distribution of the recess portion shape
based on a measurement result of the recess portion shape;
calculating a distribution of an application amount of a curing
agent to a first processing target layer based on the distribution
of the recess portion shape; applying the curing agent to the first
processing target layer based on the distribution of the
application amount of the curing agent to have a distribution of
the application amount of the curing agent in a direction of the
plane of the first processing target layer; forming a second
projection and recess pattern by transferring the first projection
and recess pattern onto the curing agent by causing the curing
agent to cure in a state where the first projection and recess
pattern is in contact with the curing agent; separating the first
projection and recess pattern from the cured curing agent; forming
a third projection and recess pattern by processing the first
processing target layer with the second projection and recess
pattern as a mask; and calculating a distribution of an application
amount of a curing agent to a second processing target layer based
on the distribution of a recess portion shape of the third
projection and recess pattern.
2. The processing method according to claim 1, wherein the recess
portion shape includes at least one of a width dimension of a
recess portion of the first projection and recess pattern, a
sidewall angle of a recess portion of the first projection and
recess pattern, and a depth of a recess portion of the first
projection and recess pattern.
3. The processing method according to claim 1, wherein the curing
agent is a photo-curing agent.
.Iadd.4. A processing method used in manufacturing semiconductor
devices, the method comprising: determining a first distribution
amount of a curing agent based on a distribution of one or more
first recess portion shapes that are associated with a first
pattern; applying the curing agent to a first processing target
layer based on the first distribution amount of the curing agent in
a direction of the plane of the first processing target layer;
obtaining a second pattern based on the first pattern; obtaining a
third pattern in the first processing target layer using the second
pattern as a mask; and determining a second distribution amount of
a curing agent for a second processing target layer based on a
distribution of one or more second recess portion shapes associated
with the third pattern..Iaddend.
.Iadd.5. The method according to claim 4, further comprising,
before determining the first distribution amount of the curing
agent: obtaining the one or more first recess portion shapes that
are associated with the first pattern, the first pattern being
associated with a template; and determining, based on the one or
more first recess portion shapes, the distribution of the one or
more first recess portion shapes that are associated with the first
pattern..Iaddend.
.Iadd.6. The method according to claim 4, wherein the one or more
recess portion shapes associated with the first pattern include at
least one of a width dimension of a recess portion, a sidewall
angle of the recess portion, and a depth of the recess
portion..Iaddend.
.Iadd.7. The method according to claim 4, wherein determining the
first distribution amount of a curing agent comprises: determining,
based on the distribution of the one or more first recess portion
shapes that are associated with the first pattern, a droplet amount
of the curing agent for each position corresponding to the first
processing target layer..Iaddend.
.Iadd.8. The method according to claim 4, wherein determining the
first distribution amount of a curing agent is further based on at
least one of the type of the curing agent, a shape of the first
pattern, a material of the first processing target layer, and one
or more etching conditions associated with the first processing
target layer..Iaddend.
.Iadd.9. The method according to claim 4, wherein applying the
curing agent to the first processing target layer comprises
applying the curing agent in one shot based on the first
distribution amount of the curing agent..Iaddend.
.Iadd.10. The method according to claim 4, wherein obtaining the
second pattern based on the first pattern comprises: causing a
template associated with the first pattern to contact the curing
agent applied to the first processing target layer; curing the
curing agent in a state where the template remains in contact with
the curing agent applied to the first processing target layer; and
separating the template from the cured curing agent to form the
second pattern..Iaddend.
.Iadd.11. The method according to claim 10, wherein causing the
template to contact the curing agent applied to the first
processing target layer comprises: moving the template associated
with the first pattern to contact the curing agent applied to the
first processing target layer; and releasing the template such that
the template can continue to move to a position at which capillary
action causes the curing agent to enter into the first
pattern..Iaddend.
.Iadd.12. The method according to claim 11, wherein the template
associated with the first pattern is warped based on the first
distribution amount of the curing agent, the warping of the
template representing an equilibrium state between the moving of
the template and the capillary action..Iaddend.
.Iadd.13. The method according to claim 10, wherein curing the
curing agent is based on ultraviolet irradiation via the
template..Iaddend.
.Iadd.14. The method according to claim 4, wherein at least one
area of the second pattern has a residual layer thickness that is
different from the residual layer thickness of other areas of the
second pattern..Iaddend.
.Iadd.15. The method according to claim 4, wherein obtaining the
third pattern in the first processing target layer using the second
pattern as a mask comprises performing at least one of: etching the
second pattern to eliminate a residual layer of the second pattern
in a first area and to reduce the thickness of a residual layer of
the second pattern in a second area, wherein the residual layer
thickness of the residual layer in the first area is less than the
residual layer thickness of the residual layer in the second area;
etching, using the etched second pattern as a mask, the first
process target layer to obtain a shape in the first area that and a
shape in the second area, wherein the shape in the first area has a
lateral dimension that is different from the lateral dimension of
the shape in the second area; and etching the shape in the first
area in a lateral direction and the shape in the second area to
obtain the third pattern, wherein the third pattern has
substantially the same lateral dimensions in the first area and in
the second area..Iaddend.
.Iadd.16. The method according to claim 15, wherein the etching is
anisotropic etching..Iaddend.
.Iadd.17. The method according to claim 4, wherein the first
pattern is associated with a template, the template being a master
template or a replica template obtained using a master
template..Iaddend.
.Iadd.18. The method according to claim 4, wherein determining the
second distribution amount of a curing agent for the second
processing target layer comprises: obtaining the one or more second
recess portion shapes that are associated with the third pattern;
determining, based on the one or more second recess portion shapes,
the distribution of the one or more second recess portion shapes
that are associated with the third pattern; and determining the
second distribution amount of the curing agent for the second
process target layer based on the distribution of the one or more
second recess portion shapes..Iaddend.
.Iadd.19. The method according to claim 4, wherein the curing agent
is a photo-curing agent..Iaddend.
.Iadd.20. A processing method used in manufacturing semiconductor
devices, the method comprising: determining a first distribution
amount of a curing agent based on a distribution of one or more
first recess portion shapes that are associated with a first
pattern; applying the curing agent to a first processing target
layer based on the first distribution amount of the curing agent in
a direction of the plane of the first processing target layer;
obtaining a second pattern based on the first pattern, wherein at
least one area of the second pattern has a residual layer thickness
that is different from a residual layer thickness of other areas of
the second pattern; and determining a second distribution amount of
a curing agent for a second processing target layer based on one or
more shapes associated with at least a part of the second
pattern..Iaddend.
.Iadd.21. The method according to claim 20, further comprising,
before determining the first distribution amount of a curing agent:
obtaining the one or more first recess portion shapes that are
associated with the first pattern, the first pattern being
associated with a template; and determining, based on the one or
more first recess portion shapes, the distribution of the one or
more first recess portion shapes that are associated with the first
pattern..Iaddend.
.Iadd.22. The method according to claim 20, wherein the one or more
recess portion shapes associated with the first pattern include at
least one of a width dimension of a recess portion, a sidewall
angle of the recess portion, and a depth of the recess
portion..Iaddend.
.Iadd.23. The method according to claim 20, wherein obtaining the
second pattern based on the first pattern comprises: causing a
template associated with the first pattern to contact with the
curing agent applied to the first processing target layer; curing
the curing agent such that the template remains in contact with the
curing agent applied to the first processing target layer; and
separating the template from the cured curing agent to form the
second pattern..Iaddend.
.Iadd.24. The method according to claim 23, wherein causing the
template to contact the curing agent applied to the first
processing target layer comprises: moving the template associated
with the first pattern to contact the curing agent applied to the
first processing target layer; and releasing the template in a
state that the template can continue to move to a position at which
capillary action causes the curing agent to enter into the first
pattern..Iaddend.
.Iadd.25. The method according to claim 20, further comprising:
etching the second pattern to eliminate a residual layer of the
second pattern in a first area and to reduce the thickness of a
residual layer of the second pattern in a second area, wherein the
residual layer thickness of the residual layer in the first area is
less than the residual layer thickness of the residual layer in the
second area; etching, using the etched second pattern as a mask,
the first process target layer to obtain a shape in the first area
that and a shape in the second area, wherein the shape in the first
area has a lateral dimension that is different from the lateral
dimension of the shape in the second area; and etching the shape in
the first area in a lateral direction and the shape in the second
area to obtain a third pattern, wherein the third pattern has
substantially the same lateral dimensions in the first area and in
the second area..Iaddend.
.Iadd.26. The method according to claim 20, wherein determining the
first distribution amount of a curing agent comprises: determining,
based on the distribution of the one or more first recess portion
shapes that are associated with the first pattern, a droplet amount
of the curing agent for each position corresponding to the first
processing target layer..Iaddend.
.Iadd.27. The method according to claim 20, wherein determining the
first distribution amount of a curing agent is further based on at
least one of the type of the curing agent, a shape of the first
pattern, a material of the first processing target layer, and one
or more etching conditions associated with the first processing
target layer..Iaddend.
.Iadd.28. The method according to claim 20, wherein applying the
curing agent to the first processing target layer comprises
applying the curing agent in one shot based on the first
distribution amount of the curing agent..Iaddend.
.Iadd.29. The method according to claim 20, wherein obtaining the
second pattern based on the first pattern comprises: causing a
template associated with the first pattern to contact the curing
agent applied to the first processing target layer; curing the
curing agent in a state where the template remains in contact with
the curing agent applied to the first processing target layer; and
separating the template from the cured curing agent to form the
second pattern..Iaddend.
.Iadd.30. The method according to claim 24, wherein the template
associated with the first pattern is warped based on the first
distribution amount of the curing agent, the warping of the
template representing an equilibrium state between the moving of
the template and the capillary action..Iaddend.
.Iadd.31. The method according to claim 29, wherein curing the
curing agent is based on ultraviolet irradiation via the
template..Iaddend.
.Iadd.32. The method according to claim 20, wherein at least one
area of the second pattern has a residual layer thickness that is
different from the residual layer thickness of other areas of the
second pattern..Iaddend.
.Iadd.33. The method according to claim 25, wherein the etching is
anisotropic etching..Iaddend.
.Iadd.34. The method according to claim 20, wherein the first
pattern is associated with a template, the template being a master
template or a replica template obtained using a master
template..Iaddend.
.Iadd.35. The method according to claim 20, wherein determining the
second distribution amount of a curing agent for the second
processing target layer comprises: obtaining a third pattern in the
first processing target layer using the second pattern as a mask;
obtaining one or more second recess portion shapes that are
associated with the third pattern; determining, based on the one or
more second recess portion shapes, a distribution of the one or
more second recess portion shapes that are associated with the
third pattern; and determining the second distribution amount of
the curing agent for the second process target layer based on the
distribution of the one or more second recess portion
shapes..Iaddend.
.Iadd.36. The method according to claim 20, wherein the curing
agent is a photo-curing agent..Iaddend.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
.[.This application.]. .Iadd.This is a reissue of U.S. Pat. No.
8,420,422, issued on Apr. 16, 2013 from U.S. patent application
Ser. No. 13/041,917, which .Iaddend.is based upon and claims the
benefit of priority from Japanese Patent Application No.
2010-64916, filed on Mar. 19, 2010.[.; the.]..Iadd.. The
.Iaddend.entire contents of .[.which.]. .Iadd.the above-identified
applications .Iaddend.are incorporated herein by reference.
FIELD
Embodiments described herein relate generally to a pattern forming
method, a processing method, and a processing apparatus.
BACKGROUND
As a method of forming a fine structure in a manufacturing process
of a semiconductor, a nanoimprint lithography (NIL) is used. The
NIL is a technology of transferring a pattern onto resist by
bringing a unit-magnification template (hereinafter, template) on
which a fine pattern that is the same size as a feature size is
formed by an electron beam (EB) exposure or the like into contact
with a process target substrate to which the resist is applied.
In such pattern formation by the NIL, resist remains in a recess
portion (corresponding to a projection portion of the template) of
a resist pattern on the process target substrate. The film
thickness of this residual portion of the resist is typically
called Residual Layer Thickness (RLT), which is an evaluation index
of process stability in the NIL.
After the NIL, a pattern is formed on the process target substrate
by etching the process target substrate with the resist pattern
formed by the NIL as a mask. As above, because resist remains also
in the recess portion of the resist pattern, an etching condition
needs to be determined by taking it also into account. In other
words, even if the dimension of the resist pattern is finished
uniformly, the pattern dimension of the processed process target
substrate may vary due to variation in RLT.
Moreover, in the NIL, a pattern formed on the template is
transferred onto resist in the same size. Therefore, accuracy in
pattern in the template greatly affects variation in final feature
size of the process target substrate. Illumination unevenness and
effect of aberration also affect the dimension variation in a shot
in a normal photolithography in addition to an error in a photomask
dimension. However, in the NIL, it can be said that most of the
dimension variation in a shot is due to the dimension variation of
the template.
On the other hand, a manufacturing accuracy is extremely severe in
the template for the NIL compared to a quadruple photomask used in
the normal photolithography. Typically, the photomask and the
template are manufactured by using an electron beam lithography.
For example, when a line and space (L/S) of 50 nm pitch is needed
on a wafer, an L/S pattern of 200 nm pitch is manufactured on the
quadruple photomask. However, on the template for the NIL, an L/S
pattern of 50 nm pitch that is the same as an actual feature size
is manufactured. Therefore, the manufacturing accuracy is severe in
the unit-magnification template for the NIL compared to the
quadruple photomask, so that variation in pattern dimension easily
occurs.
As a technology to address a problem attributed to the dimension
variation of the template, for example, Japanese Patent Application
Laid-open No. 2007-296783 proposes a method of applying resist so
that the distance between a mold and a substrate in a pressing
process becomes uniform in accordance with the shape and the
thickness distribution of the mold (template) and the process
target substrate. With this method, it is possible to shorten the
time required for the pressing process by preventing increase in
pressing time attributed to flatness such as thickness, undulation,
or the like of the mold and the process target substrate, so that
throughput can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A to FIG. 1F are cross-sectional views illustrating one
example of a manufacturing method of a template;
FIG. 2 is a diagram schematically illustrating one example of a
configuration of a nanoimprint apparatus according to a first
embodiment;
FIG. 3 is a diagram illustrating one example of distribution
information on a recess portion dimension in a pattern area surface
in the first embodiment;
FIG. 4 is a diagram illustrating one example of a distribution of a
droplet amount (application amount) of a photo-curing agent in one
shot onto a processing target layer in the first embodiment;
FIG. 5A to FIG. 5F are cross-sectional views schematically
illustrating an imprint method and a processing method using the
nanoimprint apparatus according to the first embodiment;
FIG. 6 is a diagram illustrating one example of distribution
information on a sidewall angle in a pattern area surface according
to a second embodiment;
FIG. 7 is a diagram illustrating one example of a distribution of a
droplet amount (application amount) of a photo-curing agent in one
shot onto a processing target layer in the second embodiment;
FIG. 8A and FIG. 8B are schematic diagrams explaining a shape of a
projection and recess pattern on a template in the second
embodiment;
FIG. 9A and FIG. 9B are cross-sectional views illustrating a state
where a resist pattern is formed on the processing target layer in
the second embodiment;
FIG. 10A and FIG. 10B are cross-sectional views illustrating an
initial stage of an anisotropic etching to the processing target
layer in the second embodiment;
FIG. 11 is a diagram schematically illustrating a flow of
performing a pattern formation of a process target substrate by an
NIL using a master template and a replica template according to a
third embodiment; and
FIG. 12 is a flowchart illustrating a flow of a feedback control
using shape distribution information (distribution information on a
shape parameter) on a template according to a fourth
embodiment.
DETAILED DESCRIPTION
In general, according to one embodiment, a distribution of a recess
portion shape is calculated based on a result obtained by measuring
the recess portion shape of a first projection and recess pattern
formed on a surface of a template. Next, a distribution of an
application amount of a curing agent to a processing target layer
is calculated based on the distribution of the recess portion
shape, and the curing agent is applied to the processing target
layer based on this distribution of the application amount of the
curing agent. Next, a second projection and recess pattern is
formed by transferring the first projection and recess pattern onto
the curing agent by causing the curing agent to cure in a state
where the first projection and recess pattern is in contact with
the curing agent.
It is found out through the study by the inventors that the
technology in Japanese Patent Application Laid-Open No. 2007-296783
is based on the premise that a pattern is formed on the template
with a uniform dimension and therefore cannot deal with the case
where the pattern dimension on the template varies, and thus
variation in final feature size due to the variation in pattern
dimension on the template cannot be prevented.
A pattern forming method, a processing method, and a processing
apparatus according to the embodiments will be explained below in
detail with reference to the accompanying drawings. The present
invention is not limited to these embodiments. In the following
drawings, the scale of each member is different from a realistic
one in some cases for easy understanding. The same thing can be
said between the drawings.
(First Embodiment)
In the following, a process of a nanoimprint lithography (NIL)
according to the first embodiment is explained. First, a template
substrate (hereinafter, template) used in the NIL is manufactured.
FIG. 1A to FIG. 1F are cross-sectional views illustrating one
example of a manufacturing method of the template. First, a chrome
(Cr) film 12 is formed on the whole surface of, for example, an
approximately rectangular quartz substrate 11 and resist 13 is
applied to the chrome film 12 (FIG. 1A).
Next, an electron beam (EB) writing is performed on the resist 13
by an L/S pattern of, for example, 50 nm pitch, and thereafter a
development process is performed. Consequently, an L/S resist
pattern 13p of 50 nm pitch is formed on the chrome film 12 (FIG.
1B).
Next, an anisotropic etching is performed on the chrome film 12
with the resist pattern 13p as an etching mask (FIG. 1C), and
thereafter the resist pattern 13p is stripped (FIG. 1D).
Consequently, a Cr film pattern 12p on which the pattern of the
resist pattern 13p is transferred is formed on the quartz substrate
11.
Next, the anisotropic etching is performed on the quartz substrate
11 with the Cr film pattern 12p as an etching mask. Consequently,
an L/S projection and recess pattern 11p of 50 nm pitch on which
the pattern of the Cr film pattern 12p is transferred is formed on
the surface of the quartz substrate 11 (FIG. 1E).
Next, after stripping the Cr film pattern 12p, an outside area of a
pattern area PA in which the pattern of the projection and recess
pattern 11p is formed is engraved on one surface side of the quartz
substrate 11, whereby a template 10 for nanoimprint is completed
(FIG. 1F). FIG. 1A to FIG. 15 illustrate part of the pattern area
PA in FIG. 1F in an enlarged manner.
FIG. 2 is a diagram schematically illustrating one example of a
configuration of a nanoimprint apparatus according to the first
embodiment. As shown in FIG. 2, a nanoimprint apparatus 101
according to the first embodiment includes a nanoimprint mechanism
102, a control unit 103, an input unit 104, an output unit 105, a
measuring unit 106, a distribution calculating unit 107, and an
application-amount calculating unit 108. The nanoimprint apparatus
101 is a nanoimprint apparatus in which template conveying,
substrate conveying, alignment, transfer, and the like are
automated for improving accuracy in a series of operations in
microfabrication in a semiconductor manufacturing process.
The nanoimprint mechanism 102 performs a pattern transfer onto a
substrate 21 that is a sample by the nanoimprint technology using
the template 10. The nanoimprint mechanism 102 includes a light
source 110, the template 10, template holding units 112, lift
mechanisms 113, a substrate holding unit 115, a substrate moving
mechanism 116, a substrate-movement driving unit 117, a container
118, and an application mechanism 119.
The light source 110 emits ultraviolet light L by which a
photo-curing agent is cured. The template holding units 112 hold
the template 10. The lift mechanisms 113 are provided to correspond
to the template holding units 112, respectively, and raise and
lower the template 10 in an up-and-down direction (direction of
arrows Y1 in FIG. 2) by raising and lowering the template holding
units 112. The substrate holding unit 115 holds the substrate 21.
The substrate moving mechanism 116 moves the substrate 21 in a
horizontal direction (direction of an arrow Y2 in FIG. 2) by moving
the substrate holding unit 115. The substrate-movement driving unit
117 drives the substrate moving mechanism 116. The container 118
holds a photo-curing agent to be applied to the surface of the
substrate 21. The application mechanism 119 applies the
photo-curing agent in the container 118 to a shot of a pattern
transfer target in the substrate 21. The template holding units 112
hold the template 10 so that the formation surface of the
projection and recess pattern 11p of the template 10 faces the
pattern formation target surface of the substrate 21 in
parallel.
The control unit 103 controls the operation process of each
configuration unit of the nanoimprint apparatus 101. The input unit
104 inputs instruction information on the process operation of the
nanoimprint apparatus 101. The output unit 105 outputs the process
information on the nanoimprint apparatus 101.
The measuring unit 106 measures a shape parameter for evaluating
uniformity of the shape of the projection and recess pattern 11p of
the template 10. The measuring unit 106 measures a recess portion
dimension, a sidewall angle, and an engraving amount in the
projection and recess pattern 11p as the shape parameters. The
recess portion dimension is a width of the upper portion of the
recess portion of the projection and recess pattern 11p. The
sidewall angle is an angle formed by the sidewall surface of the
recess portion of the projection and recess pattern 11p and the
main surface of the template 10. The engraving amount is a depth of
the recess portion of the projection and recess pattern 11p. The
distribution calculating unit 107 calculates distribution
information representing the distribution of the shape of the
projection and recess pattern 11p based on the measurement result
of the parameter in the measuring unit 106. The application-amount
calculating unit 108 calculates the droplet amount of the
photo-curing agent to each position onto a processing target layer
based on the calculation result in the distribution calculating
unit 107.
Next, a nanoimprint method and a processing method using the
nanoimprint apparatus 101 are explained. First, the measuring unit
106 measures the recess portion dimension of the recess portion of
the projection and recess pattern 11p as the shape parameter. Then,
the distribution calculating unit 107 calculates the distribution
information on the recess portion dimension of the projection and
recess pattern 11p based on the measurement result in the measuring
unit 106.
FIG. 3 is a diagram illustrating one example of the distribution
information on the recess portion dimension in the surface of the
pattern area PA calculated by the distribution calculating unit 107
based on the measurement result of the recess portion dimension of
the projection and recess pattern 11p in the measuring unit 106. In
FIG. 3, a width of an ellipse or an elliptical ring-shaped area
indicates the recess portion dimension. In the example shown in
FIG. 3, the recess portion dimension in the surface of the pattern
area PA has a concentric distribution. In other words, the width of
the recess portion (space) in the L/S projection and recess pattern
11p is wide in the central area in the surface of the pattern area
PA and is gradually narrowed toward the outside. The recess portion
becomes a projection portion on the substrate 21 on which a pattern
is formed by the NIL using this template 10.
On the other hand, the distribution information on the sidewall
angle and the distribution information on the engraving amount in
the surface of the pattern area PA are obtained in the similar
manner to FIG. 3 based on the measurement result of the sidewall
angle and the engraving amount of the projection and recess pattern
11p formed on the quartz substrate 11 (not shown). For the sidewall
angle and the engraving amount, the distribution in the surface of
the pattern area PA is relatively uniform. Therefore, it is
estimated that the dimension distribution in the surface of the
pattern area PA is attributed to the development process after the
EB writing. In other words, the dimension variation of the sidewall
angle and the engraving amount depends on the anisotropic etching
process (see FIG. 1E) of the quartz substrate 11 with the Or film
pattern 12p as an etching mask. If the distribution of the sidewall
angle and the engraving amount is relatively constant, variation
(distribution) in recess portion dimension of the projection and
recess pattern 11p is estimated to be caused by the development
after the EB writing.
Next, the application-amount calculating unit 108 calculates the
droplet amount of the photo-curing agent at each position in one
shot (single imprint area) to the processing target layer on which
a pattern is formed by the NIL, based on the shape information
(distribution information on the shape parameter), and determines
application amount information (distribution information) that is
information on the droplet amount of the photo-curing agent. The
application-amount calculating unit 108 can determine the
application amount information (distribution information) based on
the shape distribution information (distribution information on the
shape parameter) on the projection and recess pattern 11p by
pre-storing correspondence information on the type of a
photo-curing agent 23, the shape of the projection and recess
pattern 11p, the material of the processing target layer,
conditions such as an etching condition of the processing target
layer, and the droplet amount of the photo-curing agent.
FIG. 4 is a diagram illustrating one example of the application
amount information (distribution information) calculated by the
application-amount calculating unit 108 based on the distribution
information on the recess portion dimension calculated by the
distribution calculating unit 107. FIG. 4 illustrates
application-amount distribution information indicating the
distribution of the droplet amount of the photo-curing agent
corresponding to the distribution of the recess portion dimension
illustrated in FIG. 3, in which the size of a circle indicates the
droplet amount of the photo-curing agent. In the example shown in
FIG. 4, the droplet amount of the photo-curing agent is determined
to be small in the central portion in one shot and becomes
gradually larger toward the outside. In other words, the droplet
amount of the photo-curing agent has a concentric distribution
corresponding to the distribution of the dimension illustrated in
FIG. 3. In the present embodiment, the droplet amount of the
photo-curing agent is small in a portion in which the recess
portion dimension in the projection and recess pattern 11p is large
and is large in a portion in which the recess portion dimension in
the projection and recess pattern 11p is small. Consequently, the
RLT in the subsequent process can be intentionally controlled.
Next, the template 10 is held by the template holding units 112 and
the template holding units 112 are raised and lowered by using the
lift mechanisms 113 to arrange the template 10 at a predetermined
standby position. Moreover, the substrate 21 is held by the
substrate holding unit 115 and the substrate holding unit 115 is
moved by using the substrate moving mechanism 116 to arrange the
substrate 21 at a predetermined position. Then, the application
mechanism 119 applies the photo-curing agent 23 in one shot on a
processing target layer 22 on the substrate 21 held by the
substrate holding unit 115 based on the application amount
information (distribution information) by the control of the
control unit 103. The photo-curing agent 23 is applied such that
the application amount is small in the central portion in the
pattern area PA and becomes larger toward the outside based on the
above-described application amount information (distribution
information).
Next, the substrate moving mechanism 116 moves the substrate
holding unit 115 to arrange the substrate 21 at a predetermined
position so that the formation surface of the projection and recess
pattern 11p faces the pattern formation target surface of the
substrate 21 in parallel (FIG. 5A). FIG. 5A to FIG. 5F are
cross-sectional views schematically illustrating the imprint method
and the processing method using the nanoimprint apparatus 101.
Next, the template 10 is lowered as indicated by the arrows Y1 by
lowering the template holding units 112 by the lift mechanisms 113,
whereby the formation surface of the projection and recess pattern
11p of the template 10 is brought into contact with the
photo-curing agent 23 on the processing target layer 22 on the
substrate 21 (FIG. 5B). After the template 10 comes into contact
with the photo-curing agent 23, the driving of the lift mechanisms
113 is released and the template 10 is lowered by its own weight.
When the template 10 is moved closer to the photo-curing agent 23,
the photo-curing agent 23 enters into the projection and recess
pattern 11p of the template 10 by capillary action. In this
process, the template 10 is warped in accordance with the droplet
amount of the photo-curing agent 23 to ensure an equilibrium state
between the lowering of the template 10 by gravity and an upward
force of the photo-curing agent 23 by capillary action at each
position as illustrated in FIG. 5B.
In this state, the photo-curing agent 23 is irradiated with the
ultraviolet light L via the template 10 by the light source 110, so
that the photo-curing agent 23 is cured. After the photo-curing
agent 23 is sufficiently cured to become resist, the lift
mechanisms 113 raise the template holding units 112 to raise the
template 10 (FIG. 5C). Consequently, an L/S resist pattern 23p on
which the shape of the projection and recess pattern 11p of the
template 10 is transferred is formed on the processing target layer
22 of the substrate 21. The resist remains also in the recess
portion (space) of the resist pattern 23p. In the film thickness
(RLT) of the residual portion of the recess portion (space) of this
resist pattern 23p, the distribution of the RLT occurs in an
in-plane direction of the substrate 21. The RLT becomes thick in
the outside area in one shot in which the droplet amount of the
photo-curing agent 23 is large. On the other hand, the RLT becomes
thin in the inside (central) area in one shot in which the droplet
amount of the photo-curing agent 23 is small. Therefore, the height
of the projection portion of the resist pattern 23p from the
surface of the processing target layer 22 becomes large in the
outside area in one shot compared to the inside (central) area in
one shot by the difference of the RLT.
Next, the substrate 21 is conveyed from the nanoimprint apparatus
101 and the anisotropic etching, for example, by a dry etching is
performed on the processing target layer 22 with the resist pattern
23p as an etching mask. In the initial stage of the anisotropic
etching, in the inside (central) area in one shot in which the RLT
is thin, the resist pattern 23p is etched and thus the height
thereof becomes low. The residual portion of the recess portion of
the resist pattern 23p is eliminated by etching. Moreover, in the
outside area in one shot in which the RLT is thick, the resist
pattern 23p is etched and thus the height thereof becomes low, and
the residual portion of the recess portion of the resist pattern
23p is etched and thus the RLT becomes thin, however, the residual
portion remains (FIG. 5D).
When etching further proceeds, in the inside (central) area in one
shot in which the RLT is thin, the anisotropic etching is performed
on the processing target layer 22 with the resist pattern 23p as an
etching mask, whereby the processing target layer 22 is processed
into a shape in which the pattern of the resist pattern 23p is
transferred. At this point of time, in the inside (central) area in
one shot in which the RLT is thin, the recess portion of the
pattern of the processing target layer 22 is etched and is
eliminated. Moreover, in the outside area in one shot in which the
RLT is thick, the anisotropic etching is performed on the
processing target layer 22 with the resist pattern 23p as an
etching mask, whereby the processing target layer 22 is processed
into a shape in which the pattern of the resist pattern 23p is
transferred. At this point of time, in the outside area in one shot
in which the RLT is thick, the resist pattern 23p remains and the
recess portion of the pattern of the processing target layer 22
still remains (FIG. 5E).
When etching further proceeds, in the inside (central) area in one
shot in which the RLT is thin, etching to the processing target
layer 22 proceeds in a lateral direction and the processing target
layer 22 is processed until the width of the pattern thereof
becomes thin to a predetermined width. Moreover, in the outside
area in one shot in which the RLT is thick, the processing target
layer 22 is processed into a shape in which the pattern of the
resist pattern 23p is transferred and the recess portion of the
pattern of the processing target layer 22 is eliminated (FIG. 5F).
Consequently, in the inside (central) area in one shot and the
outside area in one shot, a processing target layer pattern 22p
having a uniform dimension same as the dimension of the resist
pattern 23p in the outside area in one shot is obtained. In this
manner, in the inside (central) area in one shot, a processing
conversion difference (difference between the dimension of the
resist pattern 23p and the dimension of the processing target layer
pattern 22p after processing) becomes large. In other words,
although the processing conversion difference is different
depending on the inside (central) area in one shot in accordance
with the RLT, the dimension of the processing target layer pattern
22p after processing finally becomes a uniform dimension same as
the dimension of the resist pattern 23p in the outside area in one
shot as illustrated in FIG. 5F.
The RLT is considered to largely depend on the droplet amount of
the photo-curing agent and the pattern coverage. When the pattern
coverage is the same, the RLT becomes thick as the droplet amount
becomes large, and when the droplet amount is the same, the RLT
becomes thin as the coverage (area in which the photo-curing agent
needs to be dropped) is high. Typically, in the case of dropping
the photo-curing agent by the inkjet method, a head including a
plurality of droplet portions that can be individually controlled
is used. When the coverage changes in the surface of the template,
the droplet amount is adjusted for each location to uniform the
RLT.
However, in the above described first embodiment, in one shot of
the processing target layer 22, in the area corresponding to the
portion (portion in which the projection portion of the resist
pattern 23p becomes wide) in which the width of the recess portion
(space) in the projection and recess pattern 11p is wide, the
droplet amount of the photo-curing agent 23 is reduced to thin the
RLT. Moreover, in one shot in the processing target layer 22, in
the area corresponding to the portion (portion in which the
projection portion of the resist pattern 23p becomes narrow) in
which the width of the recess portion (space) in the projection and
recess pattern 11p is narrow, the droplet amount of the
photo-curing agent 23 is increased to thicken the RLT.
In the area (portion in which the projection portion of the resist
pattern 23p becomes wide) in which the RLT is thin, after etching
of the processing target layer 22 proceeds and the RLT is
eliminated, the etching proceeds in a lateral direction on the
projection pattern of the processing target layer 22 and the
projection pattern of the processing target layer 22 is processed
so that the width thereof become a predetermined width. Therefore,
it is possible to process the resist pattern 23p that is formed
wide to be thin and finish the resist pattern 23p to have a width
same as the resist pattern 23p that is formed narrow. It is
possible to set so that the width of the resist pattern 23p that is
formed wide and the width of the resist pattern 23p that is formed
narrow are the same at the time when processing of the resist
pattern 23p that is formed narrow is finished by pre-storing the
correspondence information on the type of the photo-curing agent
23, the shape of the projection and recess pattern 11p, the
material of the processing target layer 22, conditions such as the
etching condition of the processing target layer 22, and the
droplet amount of the photo-curing agent and setting an appropriate
RLT based thereon.
According to the above described first embodiment, the resist
pattern 23p is formed so that the RLT is intentionally made
different for each area in one shot of the processing target layer
22 by adjusting the application amount of the photo-curing agent 23
for each area in one shot based on the shape distribution of the
projection and recess pattern 11p formed on the template 10.
Consequently, it becomes possible to control the processing
conversion difference for each area in one shot of the processing
target layer 22, i.e., difference between the dimension of the
resist pattern 23p and the dimension of the processing target layer
pattern 22p after processing and to form the processing target
layer pattern 22p having a uniform dimension in the whole area in
one shot.
In the above explanation, the case of using one template 10 is
explained, however, actually, a plurality of the templates 10 is
held by the template holding units 112 to correspond to the whole
surface of the processing target layer 22. Moreover, in the similar
manner to the normal photolithography, the nanoimprint is repeated
by the step and repeat.
Moreover, it is applicable to process the substrate 21 of the lower
layer by using the processing target layer pattern 22p formed in
the first embodiment. Consequently, it is possible to form a
pattern having a uniform dimension on the substrate 21 in the whole
area of one shot.
(Second Embodiment)
In the second embodiment, the case is explained in which each of
the recess portion dimension and the engraving amount among the
shape parameters has an approximately uniform distribution in the
surface of the pattern area PA and the sidewall angle has a
distribution in the surface of the pattern area PA. A series of
processes from the manufacturing of the template 10 to the
processing of the processing target layer 22 are basically the same
as the first embodiment. Therefore, only characteristic portions of
the second embodiment are explained below.
FIG. 6 is a diagram illustrating one example of the distribution
information on the sidewall angle in the surface of the pattern
area PA calculated by the distribution calculating unit 107 based
on the measurement result of the sidewall angle of the projection
and recess pattern 11p by the measuring unit 106. In FIG. 6, the
width between diagonal lines indicates a degree of a sidewall angle
.alpha.. Moreover, FIG. 6 illustrates the distribution of the state
same as the state in which the template 10 is set in the
nanoimprint apparatus 101, i.e., the distribution of the state when
viewed from the opposite side of the surface on which the
projection and recess pattern 11p is formed. In FIG. 6, the
difference in thickness of the width between diagonal lines is
emphatically illustrated for easy understanding. In the example
shown in FIG. 6, the sidewall angle .alpha. is 90.degree. in the
lower left area in the surface of the pattern area PA and is
80.degree. in the upper right area in the surface of the pattern
area PA, and the distribution is such that the sidewall angle
.alpha. becomes small toward the upper right area from the lower
left area in the surface of the pattern area PA. The recess portion
becomes a projection portion on the substrate 21 on which a pattern
is formed by the NIL using this template 10.
The application-amount calculating unit 108 calculates the droplet
amount of the photo-curing agent 23 at each position in one shot
onto the processing target layer 22 based on the shape distribution
information (distribution information on the shape parameter) and
determines the application amount information (distribution
information) that is information on the droplet amount of the
photo-curing agent 23.
FIG. 7 is a diagram illustrating one example of the application
amount information (distribution information) calculated by the
application-amount calculating unit 108 based on the distribution
information on the sidewall angle calculated by the distribution
calculating unit 107. FIG. 7 illustrates application-amount
distribution information indicating the distribution of the droplet
amount of the photo-curing agent 23 corresponding to the
distribution of the sidewall angle illustrated in FIG. 6, in which
the size of a circle indicates the droplet amount of the
photo-curing agent 23. In the example in FIG. 7, the droplet amount
of the photo-curing agent 23 is determined to be small in the lower
left portion in one shot and becomes larger toward the upper right
side. In other words, the droplet amount of the photo-curing agent
23 has a distribution corresponding to the distribution of the
sidewall angle illustrated in FIG. 6.
FIG. 8A and FIG. 8B are schematic diagrams illustrating the shape
of the projection and recess pattern 11p on the template 10. As
shown in FIG. 8A, in the lower left area in the surface of the
pattern area PA, the sidewall angle .alpha. is 90.degree.. As shown
in FIG. 8B, in the upper right area in the surface of the pattern
area PA, the sidewall angle .alpha. is 80.degree.. Moreover, a
recess portion dimension A of the projection and recess pattern 11p
in the lower left area in the surface of the pattern area PA
illustrated in FIG. 8A and a recess portion dimension B of the
projection and recess pattern 11p in the upper right area in the
surface of the pattern area PA illustrated in FIG. 8B are the
same.
FIG. 9A and FIG. 9B are cross-sectional views illustrating the
state where the resist pattern 23p is formed on the processing
target layer 22 of the substrate 21, which corresponds to the
process in FIG. 5C. FIG. 9A illustrates a cross section of the
resist pattern 23p in the lower left area in one shot, which is
formed by the projection and recess pattern 11p illustrated in FIG.
8A. FIG. 9B illustrates a cross section of the resist pattern 23p
in the upper right area in one shot, which is formed by the
projection and recess pattern 11p illustrated in FIG. 8B. In the
lower left portion in one shot in which the droplet amount of the
photo-curing agent 23 is small, the RLT is thin. On the other hand,
in the upper right portion in one shot in which the droplet amount
of the photo-curing agent 23 is large, the RLT is thick.
FIG. 10A and FIG. 10B are cross-sectional views illustrating an
initial stage of the anisotropic etching to the processing target
layer 22, which corresponds to the process in FIG. 5D. FIG. 10A
illustrates a cross section of the resist pattern 23p in the lower
left area in one shot, which corresponds to FIG. 9A. FIG. 10B
illustrates a cross section of the resist pattern 23p in the upper
right area in one shot, which corresponds to FIG. 9B.
When the anisotropic etching is performed, the etching proceeds in
a lateral direction in the portion in the upper right portion in
the pattern area PA in which the sidewall of the resist pattern 23p
is tilted. Therefore, a projection portion dimension a of the
resist pattern 23p illustrated in FIG. 10A and a projection portion
dimension b of the resist pattern 23p illustrated in FIG. 10B do
not become the same. In other words, the projection portion
dimension b illustrated in FIG. 10B becomes smaller than the
projection portion dimension a illustrated in FIG. 10A, and thus a
large processing conversion difference is generated.
On the other hand, in the lower left portion in the pattern area PA
in which the RLT is thin, etching proceeds in a lateral direction
as the anisotropic etching proceeds in the similar manner to the
first embodiment and the processing target layer 22 is processed
until the width of the pattern thereof becomes thin to a
predetermined width, so that a large processing conversion
difference is generated. Therefore, finally, the dimension of the
processing target layer pattern 22p after processing becomes
uniform in the lower left area and the upper right area in one shot
in the similar manner to the first embodiment.
According to the above described second embodiment, the resist
pattern 23p is formed so that the RLT is intentionally made
different for each area in one shot of the processing target layer
22 by adjusting the application amount of the photo-curing agent 23
for each area in one shot based on the shape distribution of the
projection and recess pattern 11p formed on the template 10 in the
similar manner to the first embodiment. Consequently, it becomes
possible to control the processing conversion difference for each
area in one shot of the processing target layer 22, i.e.,
difference between the dimension of the resist pattern 23p and the
dimension of the processing target layer pattern 22p after
processing and therefore to form the processing target layer
pattern 22p having a uniform dimension in the whole area in one
shot.
Moreover, it is applicable to process the substrate 21 on the lower
layer by using the processing target layer pattern 22p formed in
the second embodiment. Consequently, it is possible to form a
pattern having a uniform dimension on the substrate 21 in the whole
area of one shot.
(Third Embodiment)
FIG. 11 is a diagram schematically illustrating a flow of
performing a pattern formation of a process target substrate by the
NIL using a master template and a replica template according to the
third embodiment. In the above described first embodiment and
second embodiment, the method is illustrated in which the
processing target layer pattern 22p whose dimension is uniform in
all area in one shot is obtained by adjusting the RLT at the time
of the pattern transfer to the processing target layer 22 from the
template 10.
In the nanoimprint method, the life of the template is limited.
Therefore, a method is known in which, first, a master template 200
is manufactured in advance as illustrated in FIG. 11, a replica
template 201 is manufactured from the master template 200 by the
imprint method, and the pattern formation of a process target
substrate 202 is performed by using this replica template 201.
However, variation in pattern dimension on the template occurs also
in the master template 200. Therefore, when manufacturing the
replica template 201 from the master template 200, the RLT is
adjusted in the similar manner to the first embodiment and the
second embodiment, so that the high quality replica template 201 on
which the processed pattern having a uniform dimension is formed in
the pattern area surface can be manufactured. Then, the nanoimprint
is performed by using this replica template 201, so that the
processing target layer pattern having a uniform dimension can be
obtained. Moreover, in this case, it is applicable to adjust the
RLT again and perform the nanoimprint.
(Fourth Embodiment)
In the above described first embodiment and second embodiment, the
shape distribution information (distribution information on the
shape parameter) on the template 10 that is obtained in advance is
reflected in the recipe generation of the droplet amount of the
photo-curing agent 23, which can be called a feedforward
control.
On the other hand, it is also possible to perform a feedback
control of actually measuring the dimension of the processed
pattern formed on the process target substrate 202 as illustrated
in FIG. 12 and changing the recipe of the droplet amount of the
photo-curing agent so that the dimension variation of the processed
pattern is eliminated based on this actually-measured dimension of
the processed pattern. FIG. 12 is a flowchart illustrating a flow
of the feedback control using the shape distribution information
(distribution information on the shape parameter) of the template
10.
Specifically, first, the template manufacturing process as
explained in the first embodiment is performed (Step S110). Next,
as explained in the first embodiment and the second embodiment, the
droplet recipe of the photo-curing agent is generated based on the
shape distribution information on the template 10 (Step S120).
Next, the nanoimprint as explained in the first embodiment is
performed (Step S130). Next, etching of the processing target layer
as explained in the first embodiment is performed (Step S140).
Next, the dimension of the processed pattern of the formed
processing target layer is measured (Step S150). Then, returning to
Step S120, the recipe of the droplet amount of the photo-curing
agent is generated again based on this measured dimension of the
processed pattern so that the dimension variation from the design
dimension of the processed pattern is eliminated. For the substrate
on which the nanoimprint is, performed thereafter, after Step S140,
the system control can proceed to the next process without
performing the dimension measurement at Step S150 (Step S160).
The processed pattern having a uniform dimension can be formed even
by performing such feedback control in the similar manner to the
first embodiment and the second embodiment. In this case, it is
possible to suppress the dimension variation in not only a shot but
also between shots. In other words, in this case, it is sufficient
that the droplet amount distribution in the template is changed for
each shot.
While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to
limit the scope of the inventions. Indeed, the novel embodiments
described herein may be embodied in a variety of other forms;
furthermore, various omissions, substitutions and changes in the
form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *