U.S. patent application number 12/691685 was filed with the patent office on 2010-05-13 for fine mold and method for regenerating fine mold.
This patent application is currently assigned to Yamaha Corporation. Invention is credited to ATSUO HATTORI.
Application Number | 20100117268 12/691685 |
Document ID | / |
Family ID | 38895802 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100117268 |
Kind Code |
A1 |
HATTORI; ATSUO |
May 13, 2010 |
FINE MOLD AND METHOD FOR REGENERATING FINE MOLD
Abstract
A fine mold comprises a regeneration target film forming a
convex part of a formation surface, and a light shielding unit that
is configured deeper than a bottom of the formation surface and
that regenerates the regeneration target film. A manufacturing cost
of a product having a three-dimensional structure can be
reduced.
Inventors: |
HATTORI; ATSUO; (Iwata-shi,
JP) |
Correspondence
Address: |
Dickstein Shapiro LLP
2049 Century Park East, Suite 700
Los Angeles
CA
90067
US
|
Assignee: |
Yamaha Corporation
Hamamatsu-shi
JP
|
Family ID: |
38895802 |
Appl. No.: |
12/691685 |
Filed: |
January 21, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12604315 |
Oct 22, 2009 |
|
|
|
12691685 |
|
|
|
|
11860182 |
Sep 24, 2007 |
|
|
|
12604315 |
|
|
|
|
Current U.S.
Class: |
264/447 ;
264/219 |
Current CPC
Class: |
G03F 7/0017 20130101;
B82Y 40/00 20130101; G03F 7/0002 20130101; B82Y 10/00 20130101 |
Class at
Publication: |
264/447 ;
264/219 |
International
Class: |
B29C 59/16 20060101
B29C059/16; B29C 33/42 20060101 B29C033/42 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2006 |
JP |
2006-258571 |
Claims
1. A method of manufacturing a fine mold comprising: forming a
light shielding unit on a transparent substrate; forming a
transparent protection film on the light shielding unit; and
forming a target film on the transparent protection film, the
target film forming a convex part of a formation surface.
2. The method of manufacturing a fine mold according to claim 1,
wherein the act of forming the light shielding unit further
comprises forming the light shield unit as an opaque film.
3. The method of manufacturing a fine mold according to claim 1,
wherein the act of forming the light shielding unit further
comprises forming the light shield unit as a gradation mask.
4. The method of manufacturing a fine mold according to claim 1,
further comprising forming a shallowest depth of the light
shielding unit the same as deepest depth of the target film.
5. The method of manufacturing a fine mold according to claim 1,
wherein the transparent protection film is harder than the target
film.
6. The method of manufacturing a fine mold according to claim 1,
further comprising: forming the transparent substrate as a
transparent reinforcement plate having a concave part in which the
light shielding unit is embedded, and wherein the transparent
protection film is embedded in the transparent reinforcement plate
between the light shielding unit and the forming surface and is
formed of transparent material having a lower refractive index than
the transparent reinforcement plate.
7. The method of manufacturing a fine mold according to claim 1,
wherein the act of forming the light shielding unit further
comprises: forming a film on the transparent substrate; and
patterning the film to form the light shielding unit.
8. The method of manufacturing a fine mold according to claim 1,
wherein the act of forming the target film further comprises:
forming a photosensitive film on the transparent protective film;
exposing the photosensitive film to light through the light
shielding unit; and developing the photosensitive film to form the
target film.
9. The method of manufacturing a fine mold according to claim 1,
further comprising forming a hard film on the target film.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 12/604,315, filed Oct. 22, 2009, which is a
divisional of Ser. No. 11/860,182, filed Sep. 24, 2007, the
entirety of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] A) Field of the Invention
[0003] This invention relates to a fine mold for nanoimprinting,
etc., a method for regenerating and a transferring method with the
fine mold.
[0004] Priority is claimed to Japanese Patent Application No.
2006-258571, filed on Sep. 25, 2006, the entire contents of which
are incorporated herein by reference.
[0005] B) Description of the Related Art
[0006] Conventionally, a transfer imprinting method with a fine
mold is well-known. For example, refer to JP H05-241011, JP
2004-304097 and FUJIWARA et al "Tan-itsu shinkin saibo no
shuushukuryoku wo sokuteisuru rikigaku sensa no kaihatsu
(Development of Dynamic Sensor for Measuring Contraction Power of
Single Cardiac Myocyte)" Denkigakkai Bio-Microsystem Kenkyu-kai
Shiryo, BMS-05-3, p10-12. A product having a fine three-dimensional
structure such as a storage medium, micro electro mechanical
systems (MEMS), a micro lens, etc. can be manufactured at a low
cost by a transfer imprinting method with the fine mold.
[0007] A fine mold may be damaged by a hard alien substance on a
surface or inside of a forming material when the fine mold is
pushed to the forming material. Fine molds are expensive because
various types of them are manufactured only in small number by
using a fine processing technique such as a photolithography
technique, an electron beam exposing technique, a laser-beam direct
writing method, etc.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to reduce a
manufacturing cost of a product having a three-dimensional
structure.
[0009] According to one aspect of the present invention, there is
provided a fine mold, comprising: a regeneration target film
forming a convex part of a formation surface; and a light shielding
unit that is configured deeper than a bottom of the formation
surface and that regenerates the regeneration target film.
[0010] This fine mold has the light shielding unit that is
configured deeper than the bottom of the forming surface to
regenerate the regeneration target film forming the convex part of
the firming surface, that is, the light shielding unit is
configured in a layer near a reverse of the forming surface.
Therefore, the fine mold can regenerate the convex part by using
the light shielding unit, equipped to the fine mold, as a mask even
if the convex part is damaged. That is, a fine processing technique
is not necessary for this fine mold to regenerate the convex part.
Therefore, a cost for manufacturing a product having a fine
three-dimensional structure can be reduced by using this fine mold
in comparison to the conventional fine mold.
[0011] The light shielding unit of the fine mold according to the
invention may be formed of an opaque film. In this case, a convex
part having a rectangle shaped cross section can be regenerated by
using the light shielding unit as a mask.
[0012] The light shielding unit of the fine mold according to the
invention may be a gradation mask. In this case, a forming surface
of which surface is gently curved can be regenerated. For example,
an opaque gray tone mask having slits below a resolution of an
exposure device or a half-transparent half tone mask can be used as
the gradation mask.
[0013] According to the present invention, the shallowest depth of
the light shielding unit may be the same as the deepest depth of
the regeneration target film. In this case, there will be no
decline in a resolution caused by diffraction and dispersion when a
photosensitive for forming the regeneration target film is exposed
by using the light shielding unit as a mask.
[0014] The fine mold according to the present invention may further
comprise a transparent protection film that is harder than the
regeneration target film and configured between the forming surface
and the light shielding unit. In this case, damage to the light
shielding unit can be prevented so that the regeneration of the
forming surface will not be impossible.
[0015] The fine mold according to the present invention may further
comprise a transparent reinforcement plate having a concave part in
which the light shielding unit is embedded, and the protection film
may be embedded in the reinforcement plate between the light
shielding unit and the forming surface and formed of transparent
material having a lower refractive index than the reinforcement
plate. In this case, although the light shielding unit is separated
from the regeneration target film, total internal reflection
happens at a side of the reinforcement plate of a boundary of the
reinforcement plate and the transparent film so that there will be
no decline in a resolution caused by diffraction and dispersion
when a photosensitive for forming the regeneration target film is
exposed by using the light shielding unit as a mask.
[0016] The fine mold according to the present invention may further
comprise a transparent reinforcement plate configured at a deeper
place than the light shielding unit. In this case, strength of the
fine mold will increase.
[0017] According to another aspect of the present invention, there
is provided a method of regenerating the above-described fine mold,
comprising the steps of: removing the regeneration target film;
forming a photosensitive film on a surface from which the
regeneration target film is removed; and exposing the
photosensitive film by using the light shielding unit as a mask to
develop the photosensitive film.
[0018] According to the above-described method of regenerating the
fine mold, the regeneration target film can be regenerated without
forming a mask for forming the regeneration target film so that a
cost for manufacturing a fine structure by the transfer imprinting
method can be reduced in comparison to the conventional method.
Further, in this regeneration method according to the present
invention, the developed photosensitive film may be used as a
regeneration target film, and a regeneration target film may be
formed in an opening part of the developed photosensitive film.
[0019] The above-described method of regenerating the fine mold may
further comprise the step of pushing the fine mold to forming
material.
[0020] In this specification, a "forming surface" refers to a
surface of a fine mold composing a boundary of forming material and
the fine mold. "Transparent" a concept depending on wavelength of
light; however, in this specification, "transparent" refers to a
condition in which light of wavelengths to be used for exposure of
a photosensitive film can pass through with little or no
interruption or distortion. Similar to that, "light shielding"
refer to a condition in which the light to be used for exposure is
interrupted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1A to FIG. 1C are cross sectional views showing a fine
mold and a transfer imprinting method by using the fine mold
according to a first embodiment of the present invention.
[0022] FIG. 2A to FIG. 2C are cross sectional views showing a
manufacturing method of the fine mold according to the first
embodiment of the present invention.
[0023] FIG. 3A to FIG. 3C are cross sectional views showing the
manufacturing method of the fine mold according to the first
embodiment of the present invention.
[0024] FIG. 4A to FIG. 4C are cross sectional views showing a
regeneration method of the fine mold according to the first
embodiment of the present invention.
[0025] FIG. 5A to FIG. 5D are cross sectional views showing a fine
mold according to a second embodiment of the present invention.
[0026] FIG. 6A to FIG. 6C are cross sectional views showing a fine
mold according to a third embodiment of the present invention.
[0027] FIG. 7A to FIG. 7D are cross sectional views showing a
manufacturing method of a fine mold according to a fourth
embodiment of the present invention.
[0028] FIG. 8A to FIG. 8D are cross sectional views showing a
manufacturing method of a fine mold according to a fifth embodiment
of the present invention.
[0029] FIG. 9A and FIG. 9B are cross sectional views showing the
manufacturing method of the fine mold according to the fifth
embodiment of the present invention.
[0030] FIG. 10A to FIG. 10D are cross sectional views showing a
manufacturing method of a fine mold according to a sixth embodiment
of the present invention.
[0031] FIG. 11A to FIG. 11C are cross sectional views showing the
manufacturing method of the fine mold according to the sixth
embodiment of the present invention.
[0032] FIG. 12A to FIG. 12D are cross sectional views showing a
manufacturing method of a fine mold according to a seventh
embodiment of the present invention.
[0033] FIG. 13A to FIG. 13D are cross sectional views showing a
manufacturing method of a fine mold according to an eighth
embodiment of the present invention.
[0034] FIG. 14A to FIG. 14C are cross sectional views showing the
manufacturing method of the fine mold according to the eighth
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] The embodiments of the present invention will be described
below with reference to the drawings. In each embodiment, same
reference numbers refer to same components, and explanations for
the same components are omitted to avoid redundant.
[0036] FIG. 1A to FIG. 1C are cross sectional views showing a fine
mold and a transfer imprinting method by using the fine mold
according to a first embodiment of the present invention.
[0037] The fine mold 1 is composed by laminating a light shielding
unit 10 on a transparent substrate 11 as a reinforcement plate, a
transparent protection film 12, a resin film 13 as a regeneration
target film and a hard film 14. Since the light shielding unit 10
is configured on a layer deeper than a bottom of a formation
surface 15 having a concave part and a convex part, a resin film 13
can be regenerated by using the light shielding unit 10 as a mask.
That is, the resin film 13 can be regenerated without forming the
mask by using an expensive device for patterning the resin film 13
forming the fine concave part and the convex part of the formation
surface, and manufacturing cost of the fine mold is lower than that
of the conventional one. The regenerating method of the fine mold 1
will be described later with explanation of its manufacturing
method. Moreover, the light shielding unit 10 is not exposed on the
forming surface 15 in order not to avoid damage of the light
shielding unit 10 even if the forming surface is damaged by the
alien substance between the fine mold 1 and the forming target
substance, and not only the hard film 14 but also the protection
film 12 harder than the resin film 13 are between the light
shielding unit 10 and the forming surface 15.
[0038] Next, a transfer method used the fine mold 1 will be
explained as an example of nanoimprinting.
[0039] As shown in FIG. 1A, a forming material 91 is applied on a
surface of a substrate 92 composed of silicon wafer, etc. by spin
coating, etc. Thermoplastic resin, thermosetting resin,
photocurable resin or glass can be used as the forming material.
Moreover, the silicon wafer can be used as the forming
material.
[0040] As shown in FIG. 1B, the fine mold 1 is pushed to the
forming material 91. At this time, because the forming material
must be softened, the thermoplastic resin is heated to the glass
transition point or more in advance. There are a method to push the
forming material 91 and the fine mold 1 with two plates parallel to
each other and a method to push the forming material 91 and the
fine mold 1 by compressed air as the method to push the fine mold
1.
[0041] Next, the forming material 91 is formed by hardening. For
example, the forming material 91 is hardened by cooling in case of
the thermoplastic resin, by heating in case of the thermosetting
resin, and by irradiating ultraviolet rays in case of the
photocurable resin. Then, the concave part and the convex part of
the forming surface 15 of the fine mold 1 are transferred to the
forming material 91.
[0042] Finally, as shown in FIG. 1C, the fine mold 1 is exfoliated
from the forming material 91.
[0043] FIG. 2A to FIG. 3C are cross sectional views showing a
manufacturing method of the fine mold according to the first
embodiment of the present invention.
[0044] First, the light shielding unit 10 is formed on the
transparent substrate 11. Quartz, soda-lime glass, transparent
crystallized glass, ceramics, resin, clay, alumina, sapphire, etc.
can be used as the material of the transparent substrate 11. For
example, thickness of the transparent substrate 11 is 2 mm. Metals
such as Cr, CrO.sub.2, Cu, etc., metal oxide, etc., which are
opaque material to ultraviolet rays can be used for the material of
the light shielding unit 10. These materials can form a film on the
transparent substrate 11 by sputtering, evaporation and CVD. For
example, thickness of the light shielding unit 10 is 0.1 .mu.m. A
lamination of Cr and CrOx on the quartz and the glass used as a
mask and reticle can be used as a lamination of the light shielding
unit 10 on the transparent substrate 11.
[0045] Next, as shown in FIG. 2B, the light shielding unit 10 is
patterned by using a photoresist 50. For example, the photoresist
50 is exposed by a stepper, an aligner or an electron beam exposure
device, and a developed pattern of the photoresist 50 is
transferred to the light shielding unit 10. In the etching of the
light shielding unit 10, for example, the light shielding unit 10
consisting of Cr is anisotropically etched by ion milling or cerium
ammonium nitrite solution. The light shielding unit 10 may be
patterned by the laser direct writing method without using the
photoresist 50. In the manufacture of the mold producing various
kinds and small amount with less usage times of the reticles, the
laser direct writing method is effective for reducing the
manufacturing cost.
[0046] Next, as shown in FIG. 2C, the transparent protection film
12 is formed to cover the light shielding unit 10. SiN, a glass
with a low-melting point, AlN, SiON, TaO.sub.2, TiO.sub.2,
ceramics, resin, clay, etc., can be used as the material of the
transparent protection film 12. It is preferable that hardness of
the protection film 12 is harder than the resin film that is a
regeneration target. For example, as the film-forming method,
plasma CVD is used when SiN is the material. A surface of the
protection film 12 may be planarized by CMP and etched-back after
forming the protection film 12.
[0047] Next, as shown in FIG. 2D, the photosensitive film 51 is
formed on the protection film 12. For example, the photosensitive
film 51 is formed by applying a negative-typed photo resist with
thickness of 70 .mu.m to heat and harden.
[0048] Thereafter, as shown in FIG. 3A, an ultraviolet rays is
irradiated from a reverse side of the transparent substrate 11,
that is, from the photosensitive film 51 of the transparent
substrate 11 and the reverse side, to expose the photosensitive
film 51. At this time, the photosensitive film 51 is exposed only
in a exposure region 53 that is not shaded by the light shielding
unit 10, and the photosensitive film 51 is not exposed in an
unexposed region 52 that is shaded by the light shielding unit 10.
The light used for the exposure is not limited and can be arbitrary
selected corresponding to a design rule such as an ultraviolet ray,
a far ultraviolet ray, a deep ultraviolet ray, an extreme
ultraviolet ray and an x-ray. Of course, material of the light
shielding unit 10 can be selected corresponding to wavelength of
the light used for the exposure.
[0049] Next, when the photosensitive film 51 is developed, a resin
film 13 having a fixed pattern is formed as shown in FIG. 3B. In
FIG. 3B, a photosensitive region 53 of the negative-typed
photoresist remains. In FIG. 3B, an example that the photosensitive
region 53 becomes the resin film 13 to be the regenerating target
is shown, however; needless to say, a positive-typed photoresist
can be used as the photosensitive film 51.
[0050] Finally, as shown in FIG. 3C, a hard film 14 is formed on a
whole surface of the fine mold 1. Other inorganic material such as
metal, a metal compound, ceramics, etc. can be used as the material
of the hard film 14. Sputtering, plating and evaporation can be
used for formation of the hard film 14. A fluorine film may be
formed on the hard film 14 in order to improve mold release
property on the surface of the hard film 14.
[0051] FIG. 4A to FIG. 4C are cross sectional views showing a
regeneration method of the fine mold according to the first
embodiment of the present invention. As shown in FIG. 4A, the hard
film 14 and the resin film 13 may be deformed by alien substance
between the fine mold 1 and the forming material. When the fine
mold 1 is used in a state that the hard film 14 and the resin film
13 are deformed, the shape of the deformed forming surface 15 is
transferred to the forming material. Since the fine mold 1 has the
light shielding unit 10 as the light shielding unit on a surface
deeper than the bottom of the forming surface 15, the forming
surface 15 can be regenerated as described below.
[0052] First, as shown in FIG. 4B, the hard film 14 is removed.
When the hard film 14 is made of Ni, the hard film can be removed
by using aqueous ferric chloride solutions for etchant.
[0053] Next, as shown in FIG. 4C, the resin film 13 is removed. For
example, the resin film 13 made of a photoresist is removed by
using N-Methyl-2-pyrrolidone (NMP) and acetone. This state is just
before forming the photosensitive film 51 shown in FIG. 2D in the
manufacturing process of the fine mold 1, and after patterning the
light shielding unit 10 that becomes a mask for exposing and
developing the photosensitive film 51.
[0054] Then, as explained with reference to FIG. 2D, FIG. 3A, FIG.
3B and FIG. 3C, when the photosensitive film 51 is formed, and the
photosensitive film 51 is exposed from the reverse side of the
transparent substrate 11 to develop and form the hard film 14, the
fine mold 1 is regenerated. Moreover, the protection film 12 may be
removed and reformed, and the surface may be planalized before
forming the photosensitive film 51. Since the stepper and reticle
are not used, a processing cost after the process to form the
photosensitive film 51 shown in FIG. 2D is considerably lower than
a manufacturing cost in case of manufacturing the entire fine mold
1. That is, since the regeneration cost of the fine mold 1 is
considerably lower than the manufacturing cost of the fine mold 1,
the manufacturing cost of the substance having fine
three-dimensional shape can be further lower than the conventional
imprinting method by using the fine mold 1.
[0055] FIG. 5A to FIG. 5D are cross sectional views showing a fine
mold according to a second embodiment of the present invention. A
fine mold 2 is different from the first embodiment in a point that
the fine mold 2 has gently curving concave and convex parts on the
forming surface 15. The gently curving concave and convex parts of
the forming surface 15 depend on a cross-sectional shape of the
resin film 13. As same as the first embodiment, in the second
embodiment, a dome-shaped resin film 13 is formed by exposing the
photosensitive film 51 as shown in FIG. 5A and baking an
non-exposing region 52 of the photosensitive film 51 to reflow as
shown in FIG. 5C after developing the photosensitive film 51 as
shown in FIG. 5B.
[0056] FIG. 6A to FIG. 6C are cross sectional views showing a fine
mold according to a third embodiment of the present invention. A
fine mold 3 is different from the second embodiment in a point that
the light shielding unit 10 for forming the photosensitive film 51
is structured as a gray tone mask. A plurality of slits 111 with a
width below a resolution of the exposure device are formed on the
light shielding unit 10 that is the gradation mask. A half-exposing
region is formed on the photosensitive film 51 corresponding to the
width and the interval of the slits 111. The concave part and the
convex part gently curving along the surface of the resin film 13
obtained by developing the photosensitive film 51 in FIG. 6B can be
formed by setting the width and the interval of the slits 11 so
that the exposed condition of the half-exposed region continuously
changes. The photosensitive film 51 may be exposed from the
transparent substrate 12 in a condition that a reflection
prevention film is formed on the surface of the photosensitive film
51. Moreover, distribution of photosensitivity (reactivity) caused
by a standing wave inside the photosensitivity film 51 may be
dissolved by baking the photosensitive film 51 after exposing the
photosensitive film 51. The forming surface 15 having an
earthenware-mortar-shaped concave part can be formed by forming
plurality of the slits 111 in concentric circles.
[0057] FIG. 7A to FIG. 7D are cross sectional views showing a
manufacturing method of a fine mold according to a fourth
embodiment of the present invention.
[0058] A fine mold 4 has a half tone mask 19, the resin film 13
formed by using the half tone mask 19 and the hard film 14 covering
the resin film 13. The gently curving forming surface 15 is formed
by the resin film 13 formed by using the half tone mask 19 that is
the gradation mask. The manufacturing method of the fine mold 4 is
as follow.
[0059] First, a transmission factor of an ultraviolet ray of the
half tone mask 19 shown in FIG. 7A is set to be a desired value by
an electron beam exposure. At this time, an
earthenware-mortar-shaped concave part can be formed on the surface
of the resin film 14 exposed and developed by using the half tone
mask 19 as the mask by the exposure so that the transmission factor
of the ultraviolet ray from the surface of the half tone mask 19
decreases in proportion to the distance from a certain point.
[0060] Next, as shown in FIG. 7B, the photosensitive film 51 is
applied, and an ultra violet ray is irradiated from the reverse
side (that is, the reverse side of the surface where the
photosensitive film 51 is laminated) of the half tone mask 19.
Then, the photosensitive film 51 is exposed corresponding to the
light transmission factor of the half tone mask 19. The
photosensitive film 51 may be exposed in a state of being formed
the reflection prevention film on the surface of the photosensitive
film 51.
[0061] Next, when the photosensitive film 51 is developed, as shown
in FIG. 7C, the resin film whose surface gently curves is formed.
The photosensitive film 51 may be baked in order to resolve
distribution of the photosensitivity (reactivity) of the
photosensitive film caused by the standing wave inside the
photosensitive film 51 before developing.
[0062] Finally, when the hard film 14 is formed on the surface of
the resin film 13, the fine mold 4 shown in FIG. 7D is
completed.
[0063] In the fine mold 4, the half tone mask 19 and the resin film
13 are contacting with each other. That is, the deepest point of
the resin film as a regeneration target film and the shallowest
point of the half tone mask 19 as the light shielding unit to work
as a mask for forming the resin film 13 are agreed with each other.
Therefore, at the time of manufacturing and regenerating the fine
mold 4, when the photosensitive film 51 is exposed from the reverse
side of the half tone mask 19, that is, the reverse side of the
photosensitive film 51, there will be no decline in a resolution
caused by diffraction and dispersion of the ultraviolet ray.
[0064] FIG. 8A to FIG. 9D are cross sectional views showing a
manufacturing method of a fine mold according to a fifth embodiment
of the present invention. It is different from the first embodiment
in a point that a fine mold 5 includes the light shielding unit 10
as the light shielding unit and the protection film 20 which are
embedded in the transparent substrate 11. Moreover, it is different
from the first embodiment in a point that the depth of the
shallowest point of the light shielding unit 10 agrees with the
depth of the deepest point of the resin film 13. That is, the light
shielding unit 10 is jointed to the whole part of the wall of the
concave part of the transparent substrate 11, and the concave part
of the transparent substrate 11 is completely re-embedded by the
protection film 20 formed on the light shielding unit 10. The
manufacturing method of the fine mold 5 is as follow.
[0065] First, as shown in FIG. 8A, concave parts for embedding the
light shielding unit are formed on the surface of the transparent
substrate 11. For example, the concave parts may be formed by
photolithography using the photoresist mask 54, and the concave
parts may be formed by the laser-beam direct writing method.
[0066] Next, as shown in FIG. 8B, the light shielding unit 10 is
formed on the surface of the transparent substrate 11. The light
shielding unit 10 works as a seed layer of the protection film 20
and as the light shielding unit, for example, the light shielding
unit 10 is formed by laminating TiN.sub.X on the surface of the
transparent substrate 11 by sputtering. An adhering layer made of
Ti, Cr, etc. may be formed between the TiN.sub.x and the
transparent substrate 11.
[0067] Then, as shown in FIG. 8C, the protection film 20 is formed
on the surface of the light shielding unit 10. For example, the
protection film 20 is formed by depositing W, Ta, Ti, Mo, Cu, TiN,
TaN, MoN, etc. with a thickness of 50 .mu.m by the CVD. The opaque
protection film 20 works also as the light shielding unit. The
protection film 20 may be formed by electrolysis plating of alloy
such as NiP, NiW, NiCo, NiFe, NiMn, NiMo, etc. and metal such as
Ni, Cr.
[0068] Thereafter, as shown FIG. in 8D, the protection film 20 and
the light shielding unit 10 are removed until the transparent
substrate 11 is exposed by grinding and polishing.
[0069] Finally, as same as the first embodiment, and as shown in
FIG. 9A and FIG. 9B, when the resin film 13 and the hard film 14
are formed, the fine mold 5 is completed.
[0070] FIG. 10A to FIG. 11C are cross sectional views showing a
manufacturing method of a fine mold according to a sixth embodiment
of the present invention. It is different from the fifth embodiment
in a point that the transparent substrate 11 of a fine mold 6 is
made of a photosensitive glass having a crystallizing region 21 and
non-crystallizing region 22. The crystallizing region 21 may be
half-transparent or opaque. The manufacturing method of the fine
mold 6 is as follow.
[0071] First, as shown in FIG. 10A, the transparent substrate 11
formed of the photosensitive glass is heated after exposing a part
of the transparent substrate 11 by using, for example, the photo
mask 55 having the light shielding unit (pattern) made of CrO.sub.2
on the quartz substrate, and a crystallite is generated in the
exposing region. The exposing region becomes a crystallization
region 21. At this time, the crystallite is not generated in the
unexposed region.
[0072] Next, as shown in FIG. 10B, concave parts 24 are formed by
selectively etching the crystallizing region 21 of the transparent
substrate 11 by using diluted hydrofluoric acid.
[0073] Then, as shown in FIG. 10C, the light shielding unit 10 is
formed. For example, the light shielding unit 10 may be formed by
accumulating Ni, Co, and Cu by electroless plating, or the light
shielding unit 10 made of Ag may be formed by Tollens test.
[0074] Thereafter, as shown in FIG. 10D, the protection film 20
made of low-melting point glass is formed on the light shielding
unit 10, and the concave parts 24 are completely buried.
[0075] Then, the protection film 20 and the light shielding unit 10
are removed until the transparent substrate 11 is exposed by
grinding and polishing.
[0076] Finally, as same as the first embodiment, and as shown in
FIG. 11A, FIG. 11B and FIG. 11C, when the resin film 13 and the
hard film 14 are formed, the fine mold 6 is completed.
[0077] FIG. 12A to FIG. 12D are cross sectional views showing a
manufacturing method of a fine mold according to a seventh
embodiment of the present invention. It is different from the first
embodiment in a point that the light shielding unit 10 of a fine
mold 7 is exposed on the reverse side of the mold and that the
transparent substrate 11 itself works as the protection film of the
light shielding unit 10. The manufacturing method of the fine mold
7 is as follow.
[0078] First, as same as the first embodiment, and as shown in FIG.
12A, the light shielding unit 10 is formed on the transparent
substrate 11.
[0079] Next, as shown in FIG. 12B, the photosensitive film 51 is
formed on the reverse side of the light shielding unit 10 of the
transparent substrate 11, and an ultraviolet ray is irradiated from
the light shielding unit 10 side to expose a part of the
photosensitive film 51.
[0080] Then, as same as the first embodiment, unexposed region 52
of the photosensitive film 51 is removed, and the resin film 13
formed of the exposing region 53 is formed. Thereafter, when the
hard film 14 is formed, the fine mold 7 is completed.
[0081] FIG. 13A to FIG. 14C are cross sectional views showing a
manufacturing method of a fine mold according to an eighth
embodiment of the present invention. The shallowest part of the
light shielding unit 10 of a fine mold 8 is positioned at deeper
than the deepest point of the resin film 13 that is the
regeneration film, and it is different from other embodiments in a
point that the decline of the resolution by those embodiments is
structurally prevented.
[0082] For example, the light shielding unit 10 as the light
shielding unit is connected with the bottom of the concave part of
the transparent layer 27 as the reinforcement plate, and the
concave part of the transparent layer 27 is completely buried with
the transparent substrate 11 remained on the light shielding unit
10, and the depth of the shallowest part of the transparent
substrate 11 is same as the depth of the deepest part of the resin
film 13. The transparent substrate 11 works as the transparent
protection film of the light shielding unit 10. The material of the
transparent substrate 11 and the material of the transparent layer
27 are selected so that a refractive index of the transparent
substrate 11 is smaller than a refractive index of the transparent
layer 27.
[0083] As described in the above, a total internal reflection
occurs on both interfaces (refer to FIG. 14A) at the time of
exposing of the photosensitive film 51 by setting the refractive
index of the transparent substrate 11 and the refractive index of
the transparent layer 27. Therefore, the resolution will not
decline even though the light shielding unit 10 is positioned at
deeper than the resin film 13 that is the regenerating target film.
The manufacturing method of the fine mold 8 is as follow.
[0084] First, the light shielding unit 10 is formed on the
transparent substrate 11 as same as the first embodiment.
[0085] Next, as shown in FIG. 13A, a reinforcement substrate 26 is
joined to the reverse side of the light shielding unit 10 of the
transparent substrate 11. For example, the reinforcement substrate
26 made of glass, ceramics, metal or the likes is adhered to the
transparent substrate 11. Moreover, a metal film made of Cu or Sn
may be formed on the reverse of the transparent substrate 11 before
forming the light shielding unit 10, and this metal film may be
used as the reinforcement substrate 26.
[0086] Next, as shown in FIG. 13B, a part of the transparent
substrate 11 is removed by anisotropic etching by using the light
shielding unit 10 as the mask. At this time, it is preferable to
remove the transparent substrate 11 until the reinforcement
substrate 26 is exposed; however, an ending point of the etching
may be controlled to a depth not to expose the reinforcement
substrate 26. For example, when the transparent substrate 11 is
quartz or glass, the transparent substrate 11 is etched by RIE by
using a gas of which main component is CF.sub.4. Moreover, for
example, when the transparent substrate 11 is resin, the
transparent substrate 11 is etched by RIE by using a gas of which
main component is O.sub.2.
[0087] Next, as shown in FIG. 13C, the transparent layer 27 is
formed to bury the transparent substrate 11 and the light shielding
unit 10. Resin, glass, ceramics, clay, etc. may be used as the
material of the transparent layer 27. After forming the transparent
layer 27, it may be planarized by grinding, polishing and
etching-back the surface.
[0088] Then, as shown in FIG. 13D, the reinforcement substrate 26
is removed.
[0089] Thereafter, as same as the first embodiment, and as shown in
FIG. 14A, FIG. 14B and FIG. 14C, when the resin film 13 and the
hard film 14 are formed, the fine mold 8 is completed.
[0090] The present invention has been described in connection with
the preferred embodiments. The invention is not limited only to the
above embodiments. It is apparent that various modifications,
improvements, combinations, and the like can be made by those
skilled in the art.
[0091] For example, the hard film 14 is not always necessary, and
the protection film 12 is not always necessary. Moreover, the resin
film formed of the photosensitive film does not have to work as the
regeneration target film, but the regeneration target film may be
formed by a lift-off process by using the resin film as the mask.
Moreover, materials of the substrate and the film composing a fine
mold according to the embodiments are arbitrary selected
corresponding to the functions to be required for the fine mold,
and it is natural that the forming method and the forming
conditions of the films are arbitrary selected depending on the
material of the film and the characteristics of the film that has
already been formed.
[0092] Moreover, it is natural that the shapes and the sizes of the
forming surface of the fine molds are designed corresponding to the
shapes of what to be formed by using those molds and the design
rules. Furthermore, although the explanations of the regeneration
method of the fine mold according to the embodiments of the present
invention except the first embodiment have been omitted, it is same
as the first embodiment in a point that the regenerating target
film and the hard film are regenerated by using the light shielding
unit after removing the regenerating target film and the hard film,
and the fine mold according to each embodiment can be regenerated
by executing the latter manufacturing method explained in each
embodiment.
* * * * *