U.S. patent application number 11/468862 was filed with the patent office on 2007-04-26 for mold and imprint apparatus.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Hideki Ina, Junichi Seki, Nobuhito Suehira, Atsunori Terasaki.
Application Number | 20070090574 11/468862 |
Document ID | / |
Family ID | 37984612 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070090574 |
Kind Code |
A1 |
Terasaki; Atsunori ; et
al. |
April 26, 2007 |
MOLD AND IMPRINT APPARATUS
Abstract
In order to provide a mold and an imprint apparatus which permit
adjustment of a depth of an imprint pattern after the imprint
pattern is formed, the mold is constituted by a mold substrate
including a first material and a surface layer, constituting a
projection of the mold and including a second material, for forming
a pattern on the photocurable resin material. The first material is
more etchable than the second material. The first material and the
second material have optical transmittances capable of curing the
photocurable resin material with respect to at least a part of
wavelength range of ultraviolet light.
Inventors: |
Terasaki; Atsunori;
(Kawasaki-shi, JP) ; Seki; Junichi; (Yokohama-shi,
JP) ; Suehira; Nobuhito; (Kawasaki-shi, JP) ;
Ina; Hideki; (Tokyo, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON KABUSHIKI KAISHA
3-30-2 Shimomaruko, Ohta-ku
Tokyo
JP
|
Family ID: |
37984612 |
Appl. No.: |
11/468862 |
Filed: |
August 31, 2006 |
Current U.S.
Class: |
264/496 ;
249/114.1; 249/134; 425/174.4; 425/385 |
Current CPC
Class: |
B82Y 10/00 20130101;
B29C 2035/0827 20130101; B29C 2059/023 20130101; B29C 59/022
20130101; B29C 35/0888 20130101; G03F 7/0002 20130101; B82Y 40/00
20130101 |
Class at
Publication: |
264/496 ;
425/385; 249/114.1; 249/134; 425/174.4 |
International
Class: |
B29C 35/08 20060101
B29C035/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2005 |
JP |
257394/2005(PAT.) |
Jul 14, 2006 |
JP |
194266/2006(PAT.) |
Claims
1. A mold for imprinting a pattern on a photocurable resin
material, comprising: a mold substrate comprising a first material;
and a surface layer, constituting a projection of said mold and
comprising a second material, for forming a pattern on the
photocurable resin material; wherein the first material is more
etchable than the second material, and wherein the first material
and the second material have optical transmittances capable of
curing the photocurable resin material with respect to at least a
part of wavelength range of ultraviolet light.
2. A mold according to claim 1, wherein the first material and the
second material have a ratio of an etching rate of first material
to an etching rate of second material of not less than 10.
3. A mold according to claim 1, wherein the second material has an
optical transmittance, to light at a wavelength of 365 nm, of not
less than 30%.
4. A mold according to claim 1, wherein said surface layer
constitutes a part of the projection of said mold.
5. A mold according to claim 1, wherein said surface layer
constitutes all of the projection of said mold.
6. A mold according to claim 1, wherein the first material is
silicon oxide and the second material is selected from the group
consisting of silicon nitride, titanium oxide, aluminum oxide,
calcium fluoride, and indium tin oxide.
7. An imprint apparatus for effecting imprint by irradiating a
photocurable resin material with ultraviolet light through a mold
to cure the photocurable resin material, comprising: as the mold, a
mold according to claim 1.
8. A process for producing a device, comprising: preparing a mold
according to claim 1; causing the mold to contact a photocurable
resin material; and irradiating the photocurable resin material
with ultraviolet light through the mold.
9. A mold for imprinting a pattern on a resin material, comprising:
a mold substrate comprising a first material; and a surface layer,
constituting a projection of said mold and comprising a second
material, for forming a pattern on the photocurable resin material;
wherein the first material is more etchable than the second
material, and wherein the first material and the second material
have optical transmittances capable of being optically
measured.
10. A mold for imprinting a pattern on a photocurable resin
material, comprising: a mold substrate comprising a first material;
and a surface layer, constituting a projection of said mold and
comprising a second material, for forming a pattern on the
photocurable resin material; wherein the first material is more
etchable than the second material, and wherein the first material
and the second material have optical transmittances capable of
curing the photocurable resin material.
Description
FIELD OF THE INVENTION AND RELATED ART
[0001] The present invention relates to a mold and an imprint
apparatus.
[0002] In recent years, a fine processing technology for
transferring a fine structure on a mold onto a member to be
processed, such as a resin material or a metal material, has been
developed and has received attention. This technology is called
nanoimprint or nanoembossing and has a dissolution on the order of
several nanometers, so that expectations are growing that the
technology is used as a next-generation semiconductor fabrication
technology in place of a light exposure apparatus such as a stepper
or a scanner.
[0003] The technology can permit simultaneous processing of
three-dimensional structure, so that it is expected to be applied
to the following production technologies other than the
semiconductor fabrication technology. For example, the technology
is expected to be applied to various fields of production
technologies including those of optical devices such as photonic
crystal and those of a biochip such as micro total analysis system
(.mu.-TAS).
[0004] Application of imprint processing to the semiconductor
fabrication technology is described in, e.g., Stephan Y. Chou et
al., Appl. Phys. Lett., Vol. 67, Issue 21, pp. 3114-3116 (1995).
More specifically, a work or workpiece constituted by disposing a
layer of a photocurable resin material on a substrate such as a
semiconductor wafer is prepared. A mold having a processing surface
(surface to be processed) on which a desired imprint pattern is
formed is pressed against the work, followed by further pressure
application and irradiation with ultraviolet light (ultraviolet
rays) to cure the photocurable resin material. In this manner, the
pattern is imprinted onto the resin layer, so that the resin layer
is used as a mask to effect etching, thus performing pattern
formation on the substrate.
[0005] The processing by imprint is performed by transferring a
shape of imprint pattern including a recess and a projection formed
on a processing surface of a mold onto a member to be processed. As
a substrate for the mold on which the imprint pattern is formed,
quartz (silica or fused silica) is generally used. During etching
of the imprint pattern at the processing surface of the mask
including the quartz substrate, a layer (film) of Cr is generally
used as a hard mask. As the material for the hard mask other than
Cr, U.S. Patent Application Publication No. US2003/0205658 has
disclosed polysilicon and silicide.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide a mold
capable of adjusting a depth of an imprint pattern of the mold
after the mold is prepared.
[0007] Another object of the present invention is to provide an
imprint apparatus including the mold.
[0008] According to an aspect of the present invention, there is
provided a mold for imprinting a pattern on a photocurable resin
material, comprising:
[0009] a mold substrate comprising a first material; and
[0010] a surface layer, constituting a projection of the mold and
comprising a second material, for forming a pattern on the
photocurable resin material;
[0011] wherein the first material is more etchable than the second
material, and wherein the first material and the second material
have optical transmittances capable of curing the photocurable
resin material with respect to at least a part of wavelength range
of ultraviolet light.
[0012] The mold according to the present invention is constituted
so that it is possible to effect imprint while leaving a hard mask,
used for etching, as a surface layer without removing the hard mask
during formation of an imprint pattern onto a mold processing
surface. Further, during adjustment of a depth of the imprint
pattern, the mold is constituted so that the remaining surface
layer can be used again as a mask for etching. Based on such a
constitution, it is possible to adjust the depth of the pattern of
the mold after the mold is prepared.
[0013] These and other objects, features and advantages of the
present invention will become more apparent upon a consideration of
the following description of the preferred embodiments of the
present invention taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic sectional view showing an embodiment
of the mold according to the present invention.
[0015] FIGS. 2(a) to 2(e) are schematic sectional views for
illustrating an embodiment of preparation steps of the mold of the
present invention.
[0016] FIG. 3 is a schematic sectional view for illustrating the
case where a depth of a recess of a mold is increased after the
mold is prepared.
[0017] FIGS. 4(a) to 4(c) are schematic sectional views for
illustrating the case where a depth of a recess of a mold is
decreased after the mold is prepared.
[0018] FIGS. 5(a) and 5(b) are schematic sectional views for
illustrating another embodiment of preparation steps of the mold of
the present invention.
[0019] FIGS. 6(a) to 6(f) are schematic sectional views for
illustrating a preparation process of a device using the mold of
the present invention.
[0020] FIG. 7 is a schematic view for illustrating a constitution
of an imprint apparatus including the mold of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] A deep depth of a recess of a mold used in imprint
processing is not always better. For example, when a mold is
pressed against a resin layer as a mask layer and then is removed
from the resin layer, a shallow depth of a recess of the mold
permits easier removal of the mold. On the other hand, with respect
to a performance of the resin layer, on which a pattern is to be
formed, as a mask layer, it is desirable that the mold recess has a
deeper depth since a thicker resin layer is usable. In these
circumstances, in the case of effecting optimum imprint, it is
necessary to optimize a depth of an imprint pattern.
[0022] However, in order to change the depth of the imprint pattern
of the mold after the mold is prepared, there is no other way but
to prepare a mold once again. For this reason, further cost and
time are required, thus being inefficient. This is because
formation of the mold pattern with high definition by using an EB
exposure apparatus which has been generally used requires much cost
and time. Further, the cost and time required for the formation of
the mold pattern are cumulatively increased for each additional
preparation of mold.
[0023] In view of this problem, the inventors have come to
recognition that it is possible to effect efficient imprint when
the depth of the imprint pattern is adjustable after the mold is
prepared.
[0024] In this regard, however, it is also possible to consider
that a hard mask of Cr used during processing of mold is left
without being removed and is used as a mold for adjusting a depth
of the imprint pattern. However, the hard mask of Cr has a very low
transmittance to ultraviolet light, so that it is difficult to cure
a photocurable resin material formed on a substrate by passing
ultraviolet light through the hard mask of Cr.
[0025] Further, a hard mask of polysilicon or silicide used as the
hard mask as described in U.S. Patent Application Publication No.
US2003/0205658 also has a very low transmittance to ultraviolet
light. For this reason, it is similarly difficult to cure a
photocurable resin material formed on a substrate.
[0026] All the above described materials have very low
transmittances to ultraviolet light, so that the photocurable resin
material is not readily cured by irradiation of ultraviolet light
through these materials. As a result, there arises such a problem
that the uncured resin material is adhered to the mold to result in
contamination which impedes subsequent processing.
[0027] As described above, the conventionally used hard mask
materials such as Cr, polysilicon, and silicide are required to be
removed before the imprint is effected. For this reason, they are
not suitable for a mask for additional etching which is performed
after the mold is once processed.
[0028] The mold according to the present invention includes a mold
substrate formed of a first material and a surface layer
constituting a projection of the mold. The surface layer is formed
of a second material and is a layer for forming a pattern on a
photocurable resin material. The first material is more etchable
than the second material. Further, the first material and the
second material have optical transmittances capable of curing the
photocurable resin material with respect to at least a part of
wavelength range of ultraviolet light.
[0029] Hereinbelow, an embodiment of the present invention will be
described.
[0030] As shown in FIG. 1, a mold 103 is constituted by a mold
substrate 101 formed of a first material and a surface layer 102
formed of a second material different from the first material.
[0031] The mold 103 has an imprint pattern formed at the surface of
the mold substrate 101 and has a projection at which the surface
layer 102 is provided. The surface layer 102 is formed by leaving a
hard mask, used when the imprint pattern is formed at a processing
surface of the mold 103, as it is without removing the hard
mask.
[0032] In other words, the surface layer 102 is a layer which
remains on the mold substrate 101 without being removed when the
imprint is performed and which is used for pattern formation of a
photocurable resin material. Further, the surface layer 102 is also
a layer functioning as a mask during adjustment of a depth of the
pattern of the mold after the imprint is effected.
[0033] When the surface layer 102 is used for the pattern formation
of the photocurable resin material, it may directly contact the
photocurable resin material. Further, the surface layer 102 may
also indirectly contact the photocurable resin material through a
release agent applied onto the surface layer 102. The surface layer
102 may be constituted in a single layer form or a multilayer
form.
[0034] The first material for the mold substrate 101 and the second
material for the surface layer 102 have optical transmittances
capable of curing the photocurable resin material with respect to
light in at least a part of wavelength range of ultraviolet light.
As a result, the photocurable resin material can be cured, so that
it is possible to effect imprint of the pattern formed on the mold
surface. As the first material for the mold substrate 101, it is
possible to use silicon oxide etc. As the second material for the
surface layer 102, it is possible to use silicon nitride, titanium
oxide, aluminum oxide, calcium fluoride, indium tin oxide (ITO),
zinc oxide, etc.
[0035] Incidentally, the photocurable resin material is basically
cured by increasing an amount of light exposure unless an optical
transmittance to ultraviolet light is zero. However, in view of an
actual throughput, a somewhat high transmittance is required. For
example, in the case where a light source emitting light at a
wavelength of 365 nm is used as a light source used for a
photocuring process, a film of silicon oxide used as the first
material for the mold substrate 101 described above has an optical
transmittance of approximately 90% with respect to the 365 nm
wavelength light. Accordingly, in order not to considerably lower a
throughput compared with the case of silicon oxide as the first
material for the mold substrate 101, it is desirable that the
surface layer 102 at least has an optical transmittance of not less
than 30%.
[0036] Further, when the mold substrate 101 and the surface layer
102 provide a large difference in optical transmittance, there is a
possibility that an irregularity in degree of curing of the
photocurable resin material is caused to occur. For this reason,
the transmittances of both materials may preferably be as close as
possible. In a more preferred embodiment, the second material for
the surface layer 102 has an optical transmittance of not less than
80%.
[0037] Further, in order to effect the adjustment of depth of the
imprint pattern of the mold after the mold is prepared, it is
necessary for the first material and the second material to be a
combination such that the first material is more etchable than the
second material.
[0038] In order to selectively remove the first material, it is
necessary to increase an etching rate of the first material for the
mold substrate 101 compared with an etching rate of the second
material for the surface layer 102. In the present invention, the
first material may be substantially removed selectively, so that
some degree of the second material may also be removed. The etching
rate can be represented by a ratio of etched layer thickness to
etching time (e.g., nm/min).
[0039] In this embodiment, in order to selectively remove the first
material, by etching, compared with the second material, it is
possible to employ reactive ion etching using gas having a high C/F
ratio, such as those of C.sub.3F.sub.8, C.sub.4F.sub.8,
C.sub.5F.sub.8, and C.sub.4F.sub.6, as source gas. In the case
there the first material for the mold substrate 101 is silicon
oxide and the second material for the surface layer 102 is silicon
nitride in the above described treatment condition, a ratio of
etching rate of first material to etching rate of second material
is approximately 10-30. Further, in the same treatment condition,
the etching rate ratio of silicon oxide to a resist is
approximately 3-8. Incidentally, in the case where the surface
layer 102 is thinner than the resist mask layer, the etching rate
ratio may desirably be not less than 20.
[0040] Further, in the case of employing wet etching, it is
possible to use, e.g., hydrofluoric acid. The wet etching is
effective in formation of a pattern having a width exceeding
several ten micrometers.
[0041] The depth of the mold varies depending on a width of a
pattern to be formed but may preferably provide an aspect ratio,
defined as (depth of mold)/(minimum width of pattern to be formed),
of 0.5-10. Further, a ratio of the thickness of surface layer 102
to the depth of mold 103 may preferably be not less than 20%, e.g.,
in the case where the etching rate ratio is not less than 10 and
the number of depth adjustment is not less than 3. The thickness of
the mold substrate 101 may desirably be not less than several
micrometers in consideration of mechanical strength.
[0042] As described above, the present invention is characterized
in that the surface layer is not removed when the mold is
completed, so that it is possible to adjust a depth of a recess of
the mold even after the imprint is effected. In the mold
preparation process, a step requiring much cost and time is a step
of forming the imprint pattern. According to the present invention,
it is possible to variably change the depth of the recess of the
mold after the imprint is effected, so that it is not necessary for
the mold to be prepared again from scratch. Accordingly, it is
possible to reduce cost and time required for the pattern formation
step.
[0043] Hereinafter, the present invention will be described based
on embodiments.
Embodiment 1
[0044] A production process of a mold according to the present
invention will be described in Embodiment 1. FIGS. 2(a) to 2(e) are
sectional views for illustrating preparation steps of a mold 103 in
this embodiment.
[0045] (1) A surface layer 102 is formed in a film on a mold
substrate 101 (FIG. 2(a)). As a first material for the mold
substrate 101, silicon oxide or the like is used. As a second
material for the surface layer 102, it is possible to use silicon
nitride, titanium oxide, aluminum oxide, calcium fluoride, indium
tin oxide (ITO), zinc oxide, etc. The surface layer 102 may also be
formed in a multilayer form in addition to the single layer
form.
[0046] (2) On the surface layer 102, a resist 201 is disposed and
patterned (FIG. 2(b)). The patterning may be effected by utilizing
light exposure with a stepper or a scanner or electron beam
drawing.
[0047] (3) The surface layer 102 is etched (FIG. 2(c)).
[0048] (4) After the resist 201 is stripped, the mold substrate 101
is etched with the surface layer 102 as a mask layer (FIG. 2(d)).
The etching is performed by reactive ion etching using gas having a
high C/F ratio such as C.sub.3F.sub.8, C.sub.4F.sub.8,
C.sub.5F.sub.8 or C.sub.4F.sub.6, as source gas as described above.
Incidentally, the mold substrate 101 may also be etched by leaving
the resist 201 and using the surface layer 102 and the resist 201
as the mask layer.
[0049] In another embodiment, it is also possible to prepare a mold
of the present invention by stripping the resist 201 and then not
subjecting the mold substrate 101 to etching (FIG. 2(e)). In this
case, the surface layer 102 constitutes the entire projection of
the mold 103.
[0050] In the above embodiment, the surface layer 102 is formed on
the mold substrate 101 and thereon the resist 201 is formed. The
surface layer 102 may also be provided by using a so-called
lift-off method. More specifically, the resist 201 is formed on the
mold substrate 101 and is partially removed by etching. Then, after
the surface layer 102 is formed, the resist is stripped and then
the mold substrate 101 is etched. In this manner, it is also
possible to prepare the mold according to the present
invention.
[0051] As described above, the mold 103 having the surface layer
102, which has been used as the hard mask during formation of an
imprint pattern on a processing surface, left on the mold substrate
101 as shown in FIG. 1 is prepared.
[0052] The first material of the mold substrate 101 and the second
material for the surface layer 102 which constitute the mold 103
have optical transmittances capable of curing a photocurable resin
material with respect to light in at least a part of wavelength
range of ultraviolet light.
[0053] Accordingly, even when the surface layer 102 is not removed
but left on the mold substrate 101, it is possible to transfer the
imprint pattern of the mold 103 onto the photocurable resin
material.
[0054] Incidentally, in the conventional case where the Cr layer is
used as the hard mask for forming the imprint pattern on the mold
processing surface through etching and is subjected to etching for
re-processing while being left on the mold substrate without being
removed, there is concern about an occurrence of metal
contamination. However, in this embodiment, there is no such
concern.
Embodiment 2
[0055] A method of adjusting a depth of an imprint pattern of the
mold according to the present invention after the mold is prepared
will be described in Embodiment 2.
[0056] FIG. 3 is a sectional view for illustrating an embodiment in
the case of increasing a depth of a recess of the mold after the
mold is prepared.
[0057] In this case, additional etching of the mold substrate 101
is only effected by using the etching method described in
Embodiment 1 while using the surface layer 102 as a mask layer.
More specifically, a portion 301 at the recess of the mold
substrate 101 is etched together with a portion 302 of the surface
layer 102.
[0058] FIGS. 4(a) to 4(c) are sectional views for illustrating an
embodiment in the case of decreasing the depth of the recess of the
mold after the mold is prepared.
[0059] (1) On the entire surface of the mold 103, a material 401
identical to that of the mold substrate 101 is formed in a layer so
as to fully fill the recess of the mold 103 (FIG. 4(a)).
[0060] (2) The resultant structure is etched and flattened by
etching a portion 402 of the layer 401 (FIG. 4(b)), thus exposing
the surface of the mold 103 (FIG. 4(c)).
[0061] (3) By employing the etching method described in Embodiment
1, the remaining portion of the layer 401 is etched. More
specifically, a portion 403 of the layer 401 is etched together
with a portion 404 of the surface layer 102 (FIG. 4(c)).
[0062] As described above, it is possible to appropriately adjust
the depth of the recess of the mold 103 after the mold 103 is
prepared.
Embodiment 3
[0063] A modified embodiment of a production process of the mold
according to the present invention will be described in Embodiment
3.
[0064] FIGS. 5(a) and 5(b) are sectional views for illustrating the
modified embodiment of the mold production process.
[0065] In the case of effecting re-processing of the mold as in the
case described with reference to FIGS. 3 and 4(a) to 4(c), the
portions 302 and 404 of the surface layer 102 can also be somewhat
etched. For this reason, the thickness of the surface layer 102 may
desirably be increased. However, when a thick surface layer 102 is
etched with the resist 201 as the mask layer, a shape of a side
wall portion is deformed to lower an accuracy of pattern to be
transferred onto the mold substrate 101 is some cases. For this
reason, as shown in FIG. 5(a), an additional hard mask layer 501 is
provided between the resist 201 and the surface layer 102.
[0066] Next, by using the resist 201, the hard mask layer 501 is
etched and then the surface layer 102 is etched using the hard mask
layer 501 as a mask layer (FIG. 5(b)).
[0067] As a material for the hard mask layer 501, it is suitably
possible to use a metal material such as Cr, WSi or Al. There is no
problem even when the hard mask layer 501 is left on the surface
layer 102 during etching of the mold substrate 101 in a subsequent
step. However, the hard mask layer 501 is removed at least before
imprint.
Embodiment 4
[0068] In Embodiment 4, a device production process using the mold
of the present invention and an imprint apparatus including the
mold of the present invention will be described.
[0069] FIGS. 6(a) to 6(f) are sectional views for illustrating
production steps for effecting imprint of an imprint pattern.
[0070] First, onto a substrate 601, a photocurable resin material
602 is applied (FIG. 6(a)). Next, the mold 103 and the substrate
601 are caused to come close to and contact each other (FIG. 6(b)).
The resultant structure is irradiated with ultraviolet light 603
from a back side of the mold 103 to cure the photocurable resin
material 602 (FIG. 6(c)). Thereafter, the mold 103 is moved away
from the substrate 601 (FIG. 6(d)), and a pattern is transferred
onto the substrate 601 by etching (FIG. 6(e)). Finally, when the
photocurable resin material 602 is removed from the substrate 601,
the pattern is formed on the substrate 601 (FIG. 6(f)).
[0071] In the case of preparing a semiconductor device, examples of
the material for the substrate 601 or its surface layer may include
silicon, silicon oxide, silicon nitride, silicon carbide, an
insulating film of low dielectric constant (low-k) material,
aluminum, copper, gallium arsenide, gallium nitride, etc. Further,
in the case of preparing photonic crystal, as the material for the
substrate 601, it is possible to use silicon, titanium oxide,
gallium nitride, etc. Further, in the case of preparing a biochip,
as the material for the substrate 601, it is possible to use
silicon, silicon oxide, etc.
[0072] FIG. 7 shows a constitution of the imprint apparatus
including the mold of the present invention.
[0073] Referring to FIG. 7, the imprint apparatus includes an
exposure light source 701, a mold holding portion 702, a work
holding portion 703, a work pressing mechanism 704, an in-plane
moving mechanism 705, and an imprint control mechanism.
[0074] By the work pressing mechanism 704, the mold 103 and the
substrate 601 are caused to contact each other through the
photocurable resin material 602.
[0075] Ultraviolet light emitted from the exposure light source 701
passes through the mold holding portion 702 and the mold 103 in
this order and cures the photocurable resin material 602. Then, the
mold 103 and the substrate 601 are moved away from each other by
the work pressing mechanism 704. As desired, after the substrate
601 is moved by the in-plane moving mechanism 705, a so-called
step-and-repeat method in which transfer of the pattern in an area
adjacent to the pattern-transferred area is performed again is
effected.
[0076] Incidentally, the work pressing mechanism 704 and the
in-plane moving mechanism 705 may also be provided on the mold
holding portion 702 side.
Embodiment 5
[0077] In Embodiment 5, a mold in which the first material and the
second material described above have optical transmittances capable
of being optically measured will be described.
[0078] As described above, efficient imprint can be effected when
the depth of the imprint pattern is adjustable after the mold is
prepared. In this regard, in the conventional embodiment, as the
mold for the hard mask used during the processing of mold, it was
possible to use Cr, polysilicon, silicide, etc. It is also possible
to consider that the hard mask is used as a mask for adjusting the
depth of the imprint pattern without being removed.
[0079] However, these materials (Cr, polysilicon, and silicide)
have very low transmittances to visible light. For this reason,
e.g., in the case where a visible light source is used as a light
source for observing an alignment mark, such a problem that
alignment using the mold is not readily effected arises.
[0080] In this embodiment, the mold is a mold for imprinting a
pattern on a resin material such that it includes a mold substrate
formed of a first material; and a surface layer, constituting a
projection of the mold and formed of a second material, for forming
a pattern on the photocurable resin material. The mold is
characterized in that the first material is more etchable than the
second material, and wherein the first material and the second
material have optical transmittances capable of being optically
measured.
[0081] As the material for the mold substrate, similarly as in
Embodiment 1, silicon oxide or the like can be used. Further, as
the material for the surface layer, similarly as in Embodiment 1,
it is possible to use silicon nitride, titanium oxide, aluminum
oxide, calcium fluoride, ITO, zinc oxide, etc.
[0082] The mold in this embodiment is also applicable to other
optical measurements, such as those for a reflectance at the
substrate surface, an interference of distance between the mold and
the substrate, and absorptivity of resin material.
[0083] While the invention has been described with reference to the
structures disclosed herein, it is not confined to the details set
forth and this application is intended to cover such modifications
or changes as may come within the purpose of the improvements or
the scope of the following claims.
[0084] This application claims priority from Japanese Patent
Applications Nos. 257394/2005 filed Sep. 6, 2005 and 194266/2006
filed Jul. 14, 2006, which are hereby incorporated by
reference.
* * * * *