U.S. patent application number 11/946787 was filed with the patent office on 2008-03-27 for method for manufacturing die and molding obtained therewith.
This patent application is currently assigned to ALPS ELECTRIC CO., LTD.. Invention is credited to Munemitsu ABE, Satoru SHIMIZU, Eiji SHINOHARA, Shozo TAKAMURA.
Application Number | 20080072708 11/946787 |
Document ID | / |
Family ID | 37481562 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080072708 |
Kind Code |
A1 |
ABE; Munemitsu ; et
al. |
March 27, 2008 |
METHOD FOR MANUFACTURING DIE AND MOLDING OBTAINED THEREWITH
Abstract
A substrate 11 is patterned by photolithography to make a first
original plate. Next, the pattern 11a of the first original plate
is transferred to make a second original plate 12. Next, the second
original plate 12 is machined to make a die. Further, the pattern
12b of the second original plate 12 is transferred to make a third
original plate 13, which is used as a die. This provides a method
for manufacturing a die by which a special shape, for example, a
shape having a high aspect ratio portion can be easily formed and a
molding obtained therewith.
Inventors: |
ABE; Munemitsu; (Miyagi-ken,
JP) ; TAKAMURA; Shozo; (Miyagi-ken, JP) ;
SHIMIZU; Satoru; (Miyagi-ken, JP) ; SHINOHARA;
Eiji; (Miyagi-ken, JP) |
Correspondence
Address: |
BEYER WEAVER LLP
P.O. BOX 70250
OAKLAND
CA
94612-0250
US
|
Assignee: |
ALPS ELECTRIC CO., LTD.
1-7 Yukigaya, Otsuka-cho, Ota-ku
Tokyo
JP
|
Family ID: |
37481562 |
Appl. No.: |
11/946787 |
Filed: |
November 28, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2006/310726 |
May 30, 2006 |
|
|
|
11946787 |
Nov 28, 2007 |
|
|
|
Current U.S.
Class: |
76/107.1 |
Current CPC
Class: |
B29C 33/3878 20130101;
B29C 33/424 20130101 |
Class at
Publication: |
076/107.1 |
International
Class: |
B21K 5/20 20060101
B21K005/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2005 |
JP |
2005-164283 |
Claims
1. A method for manufacturing a die, comprising the steps of:
patterning a substrate by photolithography to make a first original
plate; transferring the pattern of the first original plate to make
a second original plate; and machining the second original plate to
make a die.
2. A method for manufacturing a die, comprising the steps of:
forming a depression in a substrate to make a first original plate;
transferring the pattern of the first original plate to make a
second original plate having a protrusion corresponding to the
depression; and machining the protrusion of the second original
plate to make a die.
3. The method for manufacturing a die according to claim 1, further
comprising the step of transferring the pattern that the die has to
make a third original plate, wherein the third original plate is
used as a die or a mother die of a die.
4. The method for manufacturing a die according to claim 2, further
comprising the step of transferring the pattern that the die has to
make a third original plate, wherein the third original plate is
used as a die or a mother die of a die.
5. A molding molded using a die, the die being obtained by the
steps of: patterning a substrate by photolithography to make a
first original plate; transferring the pattern of the first
original plate to make a second original plate; and machining the
second original plate to make a die.
6. A molding molded using a die, the die being obtained by the
steps of: forming a depression in a substrate to make a first
original plate; transferring the pattern of the first original
plate to make a second original plate having a protrusion
corresponding to the depression; and machining the protrusion of
the second original plate to make a die.
7. The molding according to claim 5, including a relatively high
aspect ratio portion.
8. The molding according to claim 6, including a relatively high
aspect ratio portion.
9. The molding according to claim 5, including at least one
selected from a group consisting of a microchannel, a microlens
array, a lens, a Fresnel lens, a reflecting mirror, and a groove
for an optical fiber.
10. The molding according to claim 6, including at least one
selected from a group consisting of a microchannel, a microlens
array, a lens, a Fresnel lens, a reflecting mirror, and a groove
for an optical fiber.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a continuation of International Application No.
PCT/JP2006/310726, filed May 30, 2006, which is incorporated herein
by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to a method for manufacturing
a die and a molding obtained therewith, and more specifically, it
relates to a method for manufacturing a die using photolithography
and machining and a molding obtained therewith.
BACKGROUND ART
[0003] With recent reduction in size, thickness, and weight of
electronics, it is hoped that special shapes, for example, a shape
having a high aspect ratio portion will be realized. Specifically,
formation of, for example, a deep groove having an arbitrarily
shaped protrusion in the bottom thereof is hoped. It is obvious
that electronics will be further reduced in size, thickness, and
weight, and it is expected that the demands for these special
shapes will increase further. In anticipation of these demands,
approaches to realizing the above special shapes, for example,
fabrication of a fine structure by photolithography using X-ray and
accuracy improvement in machining, are increasingly active.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] However, when the above special shapes are formed by
machining, the cutting tool size of processing machine is a
problem. It is difficult to process a pattern less than 100 .mu.m
in width. In addition, it is difficult to process, by machining,
what has an aspect ratio of one or more on the order of magnitude
of micrometers. On the other hand, when the above special shapes
are formed by photolithography, the processing accuracy in the
depth direction can vary about several percent. In addition,
photolithography is disadvantageous in that the controllability in
processing an arbitrary shape such as a tapered shape or a curved
shape is poor.
[0005] The present invention is made in consideration of such
points, and an object of the present invention is to provide a
method for manufacturing a die by which a special shape, for
example, a shape having a high aspect ratio portion can be easily
formed, and a molding obtained therewith.
Means for Solving the Problems
[0006] In an aspect of the present invention, a method for
manufacturing a die includes the steps of patterning a substrate by
photolithography to make a first original plate, transferring the
pattern of the first original plate to make a second original
plate, and machining the second original plate to make a die.
[0007] According to this method, photolithography is used for
forming, for example, a high aspect ratio portion in a fine
structure, and machining is used for processing an arbitrary shape
in the fine structure with a high degree of accuracy. Therefore, a
special shape, for example, a shape having a high aspect ratio
portion can be easily formed.
[0008] In another aspect of the present invention, a method for
manufacturing a die includes the steps of forming a depression in a
substrate to make a first original plate, transferring the pattern
of the first original plate to make a second original plate having
a protrusion corresponding to the depression, and machining the
protrusion of the second original plate to make a die.
[0009] According to this method, the protrusion of the second
original plate corresponding to the depression of the first
original plate is machined. Therefore, this method makes possible
complex microfabrication of a side surface or a bottom surface in a
fine depression smaller than the size of the cutting tool in
machining.
[0010] The method for manufacturing a die of the present invention
preferably includes the step of transferring the pattern that the
die has to make a third original plate, and it is preferable that
the third original plate be used as a die or a mother die of a die.
According to this method, using the third original plate as a
mother die makes it possible to obtain a die with which, for
example, a stripe groove or a fine depression or protrusion can be
formed, to an accuracy of machining, in a tapered surface or a
bottom surface of a fine structure that cannot be processed by
machining, for example, a fine structure smaller than the size of
the cutting tool used for machining. As a result, it is possible to
significantly expand the limit of die processing.
[0011] A molding of the present invention is molded using the above
die or a die obtained using the above mother die. The molding of
the present invention preferably includes a relatively high aspect
ratio portion.
Advantages
[0012] According to the method of the present invention, a
depression is formed in a substrate to make a first original plate,
the pattern of the first original plate is transferred to make a
second original plate having a protrusion corresponding to the
depression, and the protrusion of the second original plate is
machined to make a die. Therefore, a special shape, for example, a
shape having a high aspect ratio portion can be easily formed, and
a fine depression or protrusion can be easily formed by machining
with a high degree of accuracy in a tapered surface or a bottom
surface of a fine structure smaller than the size of the cutting
tool for machining.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013] Photolithography and machining have advantages and
disadvantages. That is, photolithography is advantageous to
processing a micropattern or a large area at once and to processing
a special shape. Currently, a micropattern of several tens of
nanometers in width can be formed. In addition, photolithography
enables one to process a large range at once and to form a special
shape in which the same portion needs to be processed more than
once, for example, a grating shape, and a shape having an aspect
ratio of more than 10. On the other hand, machining is advantageous
to processing with high dimensional accuracy and to processing with
small surface roughness. Machining enables processing with very
small dimensional variation.
[0014] The inventors focused attention on the above-described
points, found that a special shape, for example, a shape having a
high aspect ratio portion could be easily formed by fusing the fine
patterning by photolithography and the high-accuracy processing by
machining and thereby compensating for the disadvantage of
photolithography with machining and compensating for the
disadvantage of machining with photolithography, and made the
present invention.
[0015] That is, the gist of the present invention is to easily form
a special shape, for example, a shape having a high aspect ratio
portion by forming a depression in a substrate to make a first
original plate, transferring the pattern of the first original
plate to make a second original plate having a protrusion
corresponding to the depression, and machining the protrusion of
the second original plate to make a die.
[0016] Embodiments of the present invention will now be described
with reference to the accompanying drawings in detail. The method
for manufacturing a die according to the present invention includes
the steps of patterning a substrate by photolithography to make a
first original plate, transferring the pattern of the first
original plate to make a second original plate, and machining the
second original plate to make a die.
[0017] The method according to the present invention makes it
possible to machine a fine structure that cannot be processed with
an ordinary cutting tool 1 (whose tip width is normally 100 .mu.m
or more) used for machining and shown in FIG. 1. That is, it is
impossible to finely process (for example, to form fine depressions
and/or protrusions in) tapered surfaces 3a and a bottom surface 3b
of a depression 3 formed in a substrate 2 shown in FIG. 2 by
machining using the cutting tool 1 shown in FIG. 1. The method
according to the present invention makes it possible to make a
substrate 2 whose tapered surfaces 3a and bottom surface 3b in a
depression 3 are finely processed.
[0018] In the method according to the present invention, a
depression 4 is formed in a substrate 2 to make a first original
plate as shown in FIG. 3 (a), the pattern (depression 4) of the
first original plate is transferred to make a second original plate
5 having a protrusion 5a corresponding to the depression 4 as shown
in FIG. 3 (b), and the protrusion 5a of the second original plate 5
is machined to form tapered surfaces 5b and a top surface 5c in the
protrusion 5a as shown in FIG. 3 (c). Further, the tapered surfaces
5b and the top surface 5c are finely processed. Since the machining
is performed on the protruding portion 5a of the second original
plate 5, the machining can be performed regardless of the size of
the cutting tool 1. By thereafter transferring the machined pattern
(protrusion 5a) of the second original plate 5 to make a third
original plate, a substrate 2 having the desired shape shown in
FIG. 2 can be obtained.
[0019] The method according to the present invention will be
described in more detail. First, in the step of making the first
original plate, the substrate is patterned by photolithography as
shown in FIG. 4 (a). A resist layer (not shown) is formed on a
substrate 11. The resist layer is hardened by being irradiated with
light through a mask having a predetermined pattern. Thereafter,
the resist layer is developed to form a resist layer corresponding
to the predetermined pattern on the substrate 11. The substrate 11
is etched using the patterned resist layer as a mask. Thereafter,
the resist layer remaining on the substrate 11 is removed to form a
pattern 11a (depressed pattern in this case) on the substrate 11.
Not only the semiconductor technology, in which two-dimensional
fabrication is mainly performed, but also the MEMS (Micro
ElectroMechanical System) technology, in which three-dimensional
fabrication is performed, is utilized for the photolithography.
[0020] A silicon substrate or a plastic substrate such as a resist
layer or an acrylic substrate can be used as the substrate 11. Wet
etching, dry etching, isotropic etching, or anisotropic etching can
be used as etching. Various resists such as a negative resist or a
positive resist can be used as a resist forming the resist
layer.
[0021] By forming the pattern 11a in the substrate 11 by
photolithography in this way to make a first original plate 11, a
fine shape or a shape having a high aspect ratio (shape having a
relatively high aspect ratio of, for example, one or more on the
order of magnitude of micrometers) can be easily formed in the
first original plate.
[0022] Next, in the step of making the second original plate, the
pattern 11a of the first original plate is transferred as shown in
FIG. 4 (b). A method including transferring a pattern to a metal
layer or a plastic layer using metal electroforming or plastic
molding can be used as a method for transferring the pattern of the
first original plate. For example, by electroforming nickel on a
silicon substrate or a plastic substrate that is a substrate 11 in
which a pattern 11a is formed as described above, and peeling the
silicon substrate from the nickel plate formed by electroforming,
the pattern can be transferred to the nickel plate that is a
transfer layer. Alternatively, by forming a silicon carbide plate
on a silicon substrate patterned as described above and then
dissolving the silicon substrate, the pattern can be transferred to
the silicon carbide plate. The detail of this method is disclosed
in Toru Itoh et al., "SILICON CARBIDE MICROFABRICATION BY SILICON
LOST MOLDING FOR GLASS PRESS MOLDS," Technical Digest of
Transducers 2003, 2A2.4, pp. 254-257. The content of this document
is included in this specification for reference.
[0023] By transferring the pattern 11a of the first original plate
in this way to make a second original plate 12, the below-described
machining can be performed without limitation due to the size of
the cutting tool. If, for example, a depressed shape having a high
aspect ratio is formed in the first original plate, the pattern 11a
is inverted by being transferred to the second original plate 12
and appears as a protruding shape. Therefore, even if the size of
the depression is small, it is possible to machine the inverted
protruding pattern 11a.
[0024] Next, in the step of making a die, the second original plate
is machined as shown in FIG. 4 (c). As described above, if, for
example, a depressed shape having a high aspect ratio is formed in
the first original plate, it appears as a protruding pattern 12b in
the second original plate 12. Therefore, this protruding pattern
12b can be easily machined. This makes it possible to form a
tapered shape or a curved shape in the pattern 12b of the second
original plate 12 with a high degree of accuracy, for example, a
high degree of accuracy of .+-. 1/100.degree. or more accurate in
taper angle. That is, a part 12a of the pattern 12a can be removed
with a high degree of accuracy. The term "machining" here refers to
ordinary machining using a cutting tool.
[0025] After machined, the second original plate 12 can be used as
a die. By performing molding with this die, a molding having a
specially shaped portion, for example, a high aspect ratio portion
can be obtained. The machined second original plate 12 itself can
also be used as a processed article (processed article having a
high aspect ratio protrusion in this case). According to the
above-described method, photolithography is used for forming, for
example, a high aspect ratio portion in a fine structure, and
machining is used for processing an arbitrary shape in the fine
structure with a high degree of accuracy. Therefore, a special
shape, for example, a shape having a high aspect ratio portion can
be easily formed. According to this method, a portion requiring
high-accuracy processing is machined but the whole is not machined.
Therefore, the manufacturing process time can be shortened.
[0026] It is possible to transfer the pattern 12b of the second
original plate 12 to make a third original plate 13 as shown in
FIG. 4 (d) and to use the third original plate 13 as a die or a
mother die of a die. That is, a die may be obtained by transferring
the pattern 13a to another material using this third original plate
13 as a mother die, or the third original plate 13 may be used as a
die. Since the pattern 12b of the second original plate 12 machined
with a high degree of accuracy is transferred to this third
original plate 13, the third original plate 13 can have an
arbitrarily shaped portion, such as portion X in FIG. 4 (d), in its
fine structure. That is, the third original plate 13 has a pattern
13a including a tapered surface 13b and a bottom surface 13c finely
processed with a high degree of accuracy, which cannot be realized
by conventional arts. Therefore, by making a die using such a third
original plate 13 as a mother die and performing molding with the
die, a molding having a specially shaped portion, for example, a
high aspect ratio portion can be obtained.
[0027] Methods for transferring the pattern 12b of the second
original plate 12 to the third original plate 13 include the
following methods. For example, in the case where the second
original plate 12 is a nickel plate, another nickel plate is formed
by electroforming nickel directly on the nickel plate or with a
mold release layer therebetween, and thereafter the nickel plates
are separated to transfer the pattern to the nickel plate that is
the third original plate. In this case, the liquid composition in
nickel electroforming may be appropriately changed to change the
hardness of the nickel plate to prevent burr formation in the third
original plate. In the case where the second original plate 12 is a
silicon carbide plate, another silicon carbide plate is formed on
the silicon carbide plate with a mold release layer therebetween,
and the mold release layer is selectively dissolved to transfer the
pattern to the silicon carbide plate that is the third original
plate.
[0028] As described above, also in the case where the third
original plate 13 is used as a mother die, since the second
original plate 12 is used, it is possible to obtain a die with
which, for example, a stripe groove or a fine depression or
protrusion can be formed, to an accuracy of machining, in a tapered
surface 13b or a bottom surface 13c of a fine structure that cannot
be processed by machining and that is smaller than the size of the
cutting tool used for machining. As a result, it is possible to
significantly expand the limit of die processing.
[0029] The method for manufacturing a die of the present invention
can be applied, for example, to the manufacture of a die of a
microchannel or a microlens array. FIG. 5 (a) illustrates a
microchannel obtained by a method for manufacturing a die according
to an embodiment of the present invention. FIG. 5 (b) is an
enlarged view showing a protruding part in (a).
[0030] The microchannel 22 shown in FIG. 5 (a) is about 10 .mu.m in
width and about 20 .mu.m in depth and is formed in a substrate 21.
A plurality of protrusions 22a are provided in this microchannel
22. In addition, shallow bottom surfaces 22b and tapered surfaces
22c are formed in this microchannel 22. Such a microchannel 22
having the protrusions 22a, shallow bottom surfaces 22b, and
tapered surfaces 22c cannot be formed by machining. As for
photolithography, the taper angle .theta. shown in FIG. 5 (b)
cannot be freely set. In the case where the microchannel 22 shown
in FIG. 5 is obtained in the substrate 21 by the method of the
present invention, a groove corresponding to the microchannel 22 is
formed by photolithography in a substrate that is a first original
plate, and the pattern is transferred to a second original plate.
At this time, the groove portion corresponding to the microchannel
22 appears as a protrusion. In this protrusion, depressions
corresponding to the protrusions 22a are formed by machining. By
performing molding using the machined second original plate as a
die and using the material of the substrate 21, a substrate 21
having a microchannel 22 can be obtained.
[0031] In the case where a microlens array is obtained by the
method of the present invention, depressions corresponding to a
plurality of lenses are formed by photolithography in a substrate
that is a first original plate, and the pattern is transferred to a
second original plate. At this time, the depressions corresponding
to the lenses appear as protrusions. Finish processing (mirror-like
finishing) of these protrusions is performed by machining. By
performing molding using the machined second original plate as a
die and using the material of the lens array, a microlens array can
be obtained. When the depressions corresponding to the lenses are
formed by photolithography, the amount of light (light exposure) to
which the photosensitive resin (resist) is exposed is changed
depending on place. This makes the thickness of the photosensitive
resin after development different depending on place according to
the light exposure, thereby forming curved surfaces in the
depressions corresponding to the lenses.
[0032] The present invention is not limited to the above-described
embodiments, and various changes can be made therein. For example,
the present invention is not limited to the sizes, numerical
values, and materials described in the above-described embodiments.
Although the method of the present invention is applied to a
microchannel and a microlens array in the above-described
embodiments, the present invention is not limited to this. The
present invention can be applied to forming various shapes that
cannot be formed by photolithography alone or machining alone, for
example, a lens, a Fresnel lens, a reflecting mirror, or a groove
for an optical fiber, and combination of these, and combination of
these and a microchannel and/or a microlens array. Various other
changes can be made without departing from the scope of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a schematic view showing a cutting tool used for
machining.
[0034] FIG. 2 illustrates a shape obtained by a method for
manufacturing a die according to the present invention.
[0035] FIGS. 3 (a) to 3 (c) illustrate a method for manufacturing a
die according to an embodiment of the present invention.
[0036] FIGS. 4 (a) to 4 (d) illustrate a method for manufacturing a
die according to an embodiment of the present invention.
[0037] FIG. 5 (a) illustrates a microchannel obtained by a method
for manufacturing a die according to an embodiment of the present
invention. FIG. 5 (b) is an enlarged view showing a protrusion in
FIG. 5 (a).
REFERENCE NUMERALS
[0038] 1 cutting tool [0039] 2, 11 substrate (first original plate)
[0040] 3, 4 depression [0041] 3a, 5b, 13b, 22c tapered surface
[0042] 3b, 13c, 22b bottom surface [0043] 5, 12 second original
plate [0044] 5a protrusion [0045] 5c top surface [0046] 11a, 12b,
13a pattern [0047] 13 third original plate [0048] 21 substrate
[0049] 22 microchannel [0050] 22a protrusion
* * * * *