U.S. patent application number 10/709471 was filed with the patent office on 2005-08-04 for method of fabricating a stamper with microstructure patterns.
Invention is credited to Chen, Irene, Chen, Yih-Far, Chou, Tien-Yu, Lay, Jyh-Huei, Wang, Yuan-Hung, Zhang, Shi-Hui.
Application Number | 20050167272 10/709471 |
Document ID | / |
Family ID | 34806353 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050167272 |
Kind Code |
A1 |
Chen, Irene ; et
al. |
August 4, 2005 |
METHOD OF FABRICATING A STAMPER WITH MICROSTRUCTURE PATTERNS
Abstract
A method of fabricating a stamper with microstructure patterns
includes providing a substrate, forming a first patterned layer on
the substrate, forming a second patterned layer on the substrate
for defining an edge of the stamper, and performing an
electroforming process by taking the second pattern layer as a
growth stop wall so as to form the stamper.
Inventors: |
Chen, Irene; (Tao-Yuan
Hsien, TW) ; Chou, Tien-Yu; (Tao-Yuan Hsien, TW)
; Lay, Jyh-Huei; (Tao-Yuan Hsien, TW) ; Chen,
Yih-Far; (Tao-Yuan Hsien, TW) ; Zhang, Shi-Hui;
(Tao-Yuan Hsien, TW) ; Wang, Yuan-Hung; (Tao-Yuan
Hsien, TW) |
Correspondence
Address: |
NORTH AMERICA INTERNATIONAL PATENT OFFICE (NAIPC)
P.O. BOX 506
MERRIFIELD
VA
22116
US
|
Family ID: |
34806353 |
Appl. No.: |
10/709471 |
Filed: |
May 7, 2004 |
Current U.S.
Class: |
205/69 ;
205/70 |
Current CPC
Class: |
C25D 1/10 20130101 |
Class at
Publication: |
205/069 ;
205/070 |
International
Class: |
C25D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 2004 |
TW |
093102049 |
Claims
What is claimed is:
1. A method of fabricating a stamper with microstructure patterns,
the method comprising: providing a substrate; forming a first
patterned layer on the substrate, a pattern of the first patterned
layer being complementary to the microstructure patterns; forming a
second patterned layer on the substrate for defining an edge of the
stamper; and performing an electroforming process by taking the
second patterned layer as a growth stop wall so as to form the
stamper.
2. The method of claim 1, wherein the method further comprises
forming a seed layer above the substrate.
3. The method of claim 2, wherein the seed layer is formed on a
surface of the substrate and covers the first patterned layer so
that a pattern presented by the seed layer on the first patterned
layer is the same as the pattern of the first patterned layer.
4. The method of claim 2, wherein the seed layer is formed between
the substrate and the first patterned layer.
5. The method of claim 2, wherein the seed layer is a metal
layer.
6. The method of claim 1, wherein the substrate comprises a
conductive material.
7. The method of claim 1, wherein the second patterned layer does
not overlap the first patterned layer.
8. The method of claim 1, wherein a thickness of the second
patterned layer is greater than a thickness of the stamper.
9. The method of claim 1, wherein the first patterned layer
comprises a photosensitive material.
10. The method of claim 9, wherein the first patterned layer is a
positive photoresist layer or a negative photoresist layer.
11. The method of claim 1, wherein the second patterned layer
comprises a photosensitive material.
12. The method of claim 11, wherein the second patterned layer is a
positive photoresist layer or a negative photoresist layer.
13. The method of claim 1, wherein the first patterned layer
comprises a conductive material.
14. The method of claim 1, wherein the second patterned layer
comprises an isolating material.
15. The method of claim 1, wherein the method further comprises
releasing the stamper from the substrate so as to produce the
complete stamper without a further cutting process.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a method for fabricating a stamper,
and more particularly, to a method for fabricating a stamper
without a cutting process.
[0003] 2. Description of the Prior Art
[0004] Since injection-molding fabrication has the advantages of
easily molding products, being suitable for mass production, having
a lower production cost, and easily molding complicated products,
it has been widely applied to disk record mediums, daily
commodities, consumer electronics, and motor vehicle components and
has become a popular molding technology in plastic and metal
processing industries. In the above-mentioned injection-mold
process, the insert-mold for copying microstructure patterns of the
products plays an important role, and it may even affect the
performance of products.
[0005] The conventional fabricating method of the insert-mold
having a big size involves installing a stamper on the injection
mold for serving as the insert-mold. Generally, after the pattern
is formed on the surface of the stamper by the injection process, a
mechanical cutting process will be performed to cut the stamper
with the required size of the insert-mold. However, the prior art
mechanical cutting process often causes a slight deformation or
burr problem. As a result, the stamper may harm the smooth
injection mold, and furthermore, the problem may cause that the
injection-molding product cannot match accuracy requirements,
especially when producing optical products, such as a light guide
plate. Therefore, the conventional fabricating method of stampers
with a mechanical cutting process may cost more fabricating time,
and cannot reach the accuracy requirement of the cutting
process.
[0006] Furthermore, when the stamper is applied to super-precise or
micron-injection molding processes for electronic and optical
products, an improved technology, electroforming process, may be
used to produce the entire stamper directly for forming the precise
microstructure patterns on the stamper. However, the electroforming
process has a problem that the size of produced stamper is limited
with the electroforming equipment and the size of produced stamper
is larger than the required size. Generally speaking, the produced
stamper has the same size as the substrate carrying the produced
stamper of the electroforming equipment, thus the redundant portion
of the electroformed stamper has to be cut for making the stamper
match the injection mold. Therefore, the fabrication of stampers
with the electroforming process still has the problem of
deformation and burr resulting from the cutting process.
SUMMARY OF INVENTION
[0007] It is therefore a primary objective of the claimed invention
to provide a method of fabricating a stamper that uses a growth
stop wall in an electroforming process to solve the above-mentioned
problem.
[0008] According to the claimed invention, the method of
fabricating a stamper with microstructure patterns comprises
providing a substrate, forming a first patterned layer on the
substrate, which has a pattern complementary to the microstructure
patterns of the predetermined stamper, forming a second patterned
layer on the substrate for defining an edge of the stamper, and
performing an electroforming process by taking the second patterned
layer as a growth stop wall so as to form at least one
predetermined stamper.
[0009] It is an advantage of the claimed invention that the second
patterned layer serving as a growth stop wall is formed on the
substrate before the electroforming process, so that the
electroformed stamper can have a predetermined size fitting the
injection mold. As a result, the electroformed stamper does not
need to be further fabricated with a mechanical cutting process,
and the problem of deformation and burr resulting from the
conventional mechanical cutting process can be avoided.
[0010] These and other objectives of the claimed invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment, which is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIGS. 1-7 are schematic diagrams of a first embodiment of
fabricating a stamper according to the present invention.
[0012] FIG. 8 is a schematic diagram of a third embodiment of
fabricating a stamper according to the present invention.
DETAILED DESCRIPTION
[0013] Please refer to FIGS. 1-7, FIGS. 1-7 are schematic diagrams
of the first embodiment of fabricating a stamper according to the
present invention. As shown in FIG. 1, a substrate 10 is provided,
which may be a clean glass substrate or another isolating
substrate. Then, a photoresist layer 12 is coated on the substrate
10, and a photolithography process is performed to transfer a
designed pattern to the photoresist layer 12. After a development
process, a first patterned layer 12 as shown in FIG. 2 is formed.
The pattern of the first patterned layer 12 is complementary to the
microstructure patterns of the predetermined stamper. In this
embodiment, the first patterned layer 12" is formed with a
photosensitive material, which is not limited to a positive
photoresist material or a negative photoresist material.
[0014] Referring to FIG. 3, a thin seed layer 14 is formed on the
surface of the substrate 10 and the first patterned layer 12, which
closely and precisely covers the first patterned layer 12 and the
substrate 10, so that the seed layer 14 has a pattern approximately
the same as the pattern of the first patterned layer 12. The main
functionality of the seed layer 14 is to adsorb electroforming
metal materials. Accordingly, the thickness of the seed layer 14
depends on the requirements of the fabrication process, wherein the
thickness of the seed layer 14 can be designed with the unit of
nanometer (nm). For accomplishing the function of the seed layer
14, preferably, its material is a conductive metal, such as nickel
or silver. The seed layer 14 is formed by the way of sputtering,
evaporation, or electroless-plating processes. Furthermore,
nonmetallic conductive materials, such as a carbon film, can also
be used as the seed layer 14.
[0015] Please refer to FIG. 4, after forming the seed layer 14, a
second patterned layer 16 comprising isolating material is formed
on the substrate 10. In this embodiment, the second patterned layer
16 is a photosensitive material, such as a positive photoresist
material or negative photoresist material. The pattern of the
second patterned layer 16 is defined by a photolithography process
that exposes a photomask with a specific pattern and a development
process so as to transfer the specific pattern onto the second
patterned layer 16. It should be noted that the second patterned
layer 16 of the present invention serves as a growth stop wall
during the electroforming process, and therefore the pattern of the
second patterned layer 16 defines the size and edge of the
predetermined stamper. As a result, the second patterned layer 16
is thick and ranges from hundreds to thousands of micrometers
(.mu.m), depending on the fabricating process, provided that the
second patterned layer 16 is thicker than the predetermined
stamper.
[0016] Please refer to FIG. 5. FIG. 5 is a top view of the
substrate 10, the second patterned layer 16, and the seed layer 14
shown in FIG. 4. Since the first patterned layer 12" is used for
forming the microstructure patterns of the stamper, and the second
patterned layer 16 is used to define the edge of the stamper, both
of the patterns of the first and second patterned layers 12, 16 are
staggered on the surface of the substrate 10, which means the
second patterned layer 16 does not overlap the first patterned
layer 12. As shown in FIG. 5, a portion of the seed layer 14 covers
the surface of the first patterned layer 12 protruding from the
substrate 10, and the second patterned layer 16 surrounds the first
patterned layer 12.
[0017] Then, referring to FIG. 6, an electroforming process is
performed to make metal materials adsorbed and grow along the
surface of the seed layer 14, but not adsorbed on the surface of
the isolating second patterned layer 16. Therefore, two
predetermined stampers 18a and 18b are formed on the substrate 10.
As in the above description, the electroformed stampers 18a and 18b
have to be thinner than the second patterned layer 16 so that the
second patterned layer 16 can have the function of being a growth
stop wall in order to limit the sizes of the stampers 18a and 18b
inside the area surrounded by the second patterned layer 16.
Accordingly, the electroformed stampers 18a and 18b have fixed
sizes and do not need to sustain a further cutting process or an
extra fabricating process.
[0018] Finally, as shown in FIG. 7, a releasing process is
performed to make the stampers 18a and 18b release from the
substrate 10, the second patterned layer 16, and the first
patterned layer 12 so as to produce complete stampers 18a and 18b
that do not need to be further cut and are capable of being
directly installed in injection molds as insert-molds. In addition,
if the material of the seed layer 14 is as same as the material of
the stampers 18a and 18b, for example, both of the materials of the
seed layer 14 and the stampers 18a and 18b are nickel, the seed
layer 14 on the surface of the stampers 18a and 18b does not have
to be removed. Instead, the seed layer 14 can be kept on the
released stampers 18a and 18b and be taken as mold-inserts
together. On the other hand, when the material of the seed layer 14
is different from that of the stampers 18a and 18b, the seed layer
14 has to be removed from the surface of the stampers 18a and 18b
during the releasing process.
[0019] In the second embodiment of the present invention, the first
patterned layer and the second patterned layer are
non-photosensitive materials. Taking the first patterned layer as
an example, the formation process may comprise forming a
non-photosensitive material layer and a photoresist layer on the
substrate sequentially, performing a photolithography process to
transfer a pattern to the photoresist layer, then performing a
development process, taking the patterned photoresist layer as an
etching mask to etch the non-photosensitive material layer, and
finally, removing the photoresist layer so as to form the first
patterned layer. The formation process of the second patterned
layer with a non-photosensitive material may be similar to the
above-mentioned formation process of the first patterned layer, and
therefore no extraneous description will be provided herein.
[0020] Please refer to FIG. 8, which is a schematic diagram of a
third embodiment of fabricating a stamper according to the present
invention. In the third embodiment of the present invention, the
seed layer 32 is formed between the substrate 30 and the first
patterned layer 34. Accordingly, the seed layer 32 is formed on the
surface of the substrate 10 before the first patterned layer 34,
and then the first patterned layer 34 and the second patterned
layer 36 are formed on the seed layer 32. It should be noted that
since the first patterned layer 34 does not overlap the second
patterned layer 36, the sequence of the formation of the first and
second patterned layers 34, 36 is not limited. Furthermore, the
first and second patterned layers 34, 36 may be formed with the
same material layer. For example, when the first and the second
patterned layer 34, 36 are formed with the same material layer,
several patterned photoresist layers may be used to etch a
non-photosensitive material layer to form the first and the second
patterned layers 34, 36 with different thickness because the second
patterned layer 36 has to be thicker than the stamper 38a, 38b and
the first patterned layer 34 has to be thinner than the stampers
38a, 38b. On the other hand, in order to gain a better performance
of the electroforming process, the first patterned layer 34 can be
formed with conductive materials selectively for ensuring the
surfaces of the stampers 38a, 38b have microstructure patterns
precisely close to the first patterned layer 34.
[0021] In the fourth embodiment of the present invention, a
conductive substrate is used. And the first patterned layer for
defining the microstructure patterns and the second patterned layer
for defining the edge of the stamper are formed on the conductive
substrate. Then, the second patterned layer is taken as a growth
stop wall to perform an electroforming process to form stampers.
Similarly, the first patterned layer can be formed with conductive
materials selectively in order to improve the electroforming
performance.
[0022] In contrast to the prior art, the present invention employs
two photolithography processes and an electroforming process to
fabricate the stampers having predetermined shapes without a
further cutting process. The main theory of the present invention
takes the second patterned layer formed with isolating material as
a growth stop wall when electroforming the stampers. Therefore, the
produced stampers can have predetermined shapes and sizes. Although
the first and third embodiments both introduce the present
invention method by fabricating two rectangular stampers
simultaneously, the amount and shape of stampers that can be
produced through a single electroforming process is not limited by
those embodiments. Adopting the present invention to produce
stampers can avoid the problems of deformation and burr caused by
conventional mechanical cutting process, and can produce stampers
with accurate sizes. Accordingly, the fabrication time and cost can
be saved.
[0023] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *