METHOD OF FABRICATING A STAMPER WITH MICROSTRUCTURE PATTERNS
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.
1. Field of the Invention
The invention relates to a method for fabricating a stamper, and more particularly, to a method for fabricating a stamper without a cutting process.
2. Description of the Prior Art
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.
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.
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 INVENTIONIt 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.
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.
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.
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
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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.
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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.
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.
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.
Claims
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.
Type: Application
Filed: May 7, 2004
Publication Date: Aug 4, 2005
Inventors: Irene Chen (Tao-Yuan Hsien), Tien-Yu Chou (Tao-Yuan Hsien), Jyh-Huei Lay (Tao-Yuan Hsien), Yih-Far Chen (Tao-Yuan Hsien), Shi-Hui Zhang (Tao-Yuan Hsien), Yuan-Hung Wang (Tao-Yuan Hsien)
Application Number: 10/709,471