JPH11306604A - Stamper manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a stamper in satisfactory yield, which carries pits which are to be used at the time of duplicating a record medium having a recording layer which carries minute ruggedness (hereinafter referred to as pits) of an optical disk or the like, from a master disk. SOLUTION: This stamper manufacturing method includes a master stamper forming process in which a master stamper 8 is electrically casted by making a master disk a die and the master stamper 8 is stripped off from a glass master disk 1, a mother stamper forming process in which a mother stamper 9 is electrically casted by making the master stamper 8 a die and the mother stamper 9 is stripped off from the master stamper 8 and a process in which a stamper 10 is electrically casted by making the mother stamper 9 a die and the stamper 10 is stripped off from the mother stamper 9 and which manufactures a stamper having minute ruggedness and sheet thicknesses of the master stamper 8 and the mother stamper 9 are 0.01 to 0.2 mm and the sheet thickness of the mother stamper 9 is made to be equal to or thicker than that of the master stamper 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention resides in a method of manufacturing a stamper having pits used when copying a recording medium having a recording layer having minute irregularities (hereinafter referred to as "pits") such as an optical disk from a master. More specifically, the present invention resides in a method for manufacturing a stamper with high yield.

[0002]

2. Description of the Related Art Conventionally, compact discs (hereinafter, referred to as compact discs)
It is called CD. In order to prepare a stamper for the duplication of (1), a stamper manufacturing method as shown in FIG. 4 is generally known. First, as shown in FIG. 4A, a photoresist is uniformly applied to the surface of the flat glass master 1 by spin coating or the like, and dried to form a thin film of the photoresist 2.

[0003] Next, as shown in FIG. 4 (b), a master (usually glass) 1 carrying a photoresist 2 is mounted on a cutting device, and a laser lighted by a predetermined signal while rotating the glass master 1. Photoresist 2 on a glass master 1 that rotates a heat ray 3 such as a beam through an objective lens 4
Irradiation. In this way, a spiral or a groove of a concentric master which carries a predetermined signal or a pit row is formed on the photoresist 2 as a latent image. Thus, FIG.
As shown in (c), after development of the glass master 1 with the photoresist 2, a glass master having irregularities 5 and 6 corresponding to grooves or pit rows is formed.

[0004] Next, as shown in FIG. 4 (d), a conductive film 7 of silver, nickel, or an alloy thereof is formed on the photoresist 2 of the glass master 1 by a sputtering method or the like. 5 is made conductive. Next, FIG.
As shown in (1), the glass master 1 having the conductive film 7 is immersed in an electroforming tank, and a master stamper 8 made of nickel or the like is electroformed on the conductive film 7. This thickness is usually about 0.3mm
It is.

[0005] Next, as shown in FIG. 4 (f), the electroformed master stamper 8 is peeled from the glass master 1, and the photoresist 2 remaining on the surface of the master stamper 8 is washed to remove the master stamper 8. obtain. Next, as shown in FIG. 4 (g), a release layer is provided on the surface of the master stamper 8 as necessary, and then the master stamper 8 is immersed in an electroforming tank to form a mother stamper made of nickel or the like on the uneven surface of the master stamper 8. 9 is electroformed. The thickness of the mother stamper is usually about 0.3 mm.

Next, as shown in FIG. 4H, the electroformed mother stamper 9 is peeled off from the master stamper 8 to obtain a mother stamper 9. By repeating these steps, several mother stampers 9 can be obtained. next,
As shown in FIG. 4 (i), a release layer is provided on the surface of the mother stamper 9 as required, and then the stamper 10 is immersed in an electroforming tank to electroform the stamper 10 on the mother stamper 9. The thickness of the stamper is usually about 0.3 mm. Finally, FIG.
As shown in (j), the electroformed stamper 10 is separated from the mother stamper 9 to obtain the stamper 10. Usually a nickel stamper. By repeating these steps, several tens more stampers 10 can be obtained.

[0007]

However, there has been no problem in applying such a manufacturing method of the stamper 10 to a conventional manufacturing method of a stamper for an optical disk such as a CD. When used in the manufacture of optical discs (for example, DVDs) for use, it was found from the observation of electron micrographs that the pits were broken as if they were shaved. This collapse occurs in a direction shown in FIG. 5 when the mother stamper 9 is peeled off from the master stamper 8 or when the stamper 10 is peeled off from the mother stamper 9 because the stamper has minute pits. As a result of the displacement of the surface, the ends of the minute pits rub each other.
It is considered that this collapse occurs due to the twisting as described above.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stamper manufacturing method for manufacturing a stamper with less pit collapse. In particular, the stamper manufacturing method of the present invention is particularly effective for a method of manufacturing a stamper having minute irregularities, which is used for manufacturing an optical disc for high-density recording. A master stamper forming step of removing the stamper, an electroforming of the mother stamper using the master stamper as a mold, a mother stamper forming step of removing the mother stamper from the master stamper, and an electroforming of the stamper using the mother stamper as a mold. A stamper manufacturing method for producing a stamper having minute irregularities, including a stamper forming step of peeling off the stamper, wherein the thickness of the master stamper and the mother stamper is 0.01 to 0.20 mm, and the thickness of the mother stamper is The thickness of the master stamper Resides in the lymph manufacturing method.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The stamper manufacturing method according to the present embodiment includes the following steps almost similarly to the conventional method. 1) Electroforming a master stamper 8 having a thickness of about 0.13 mm using a glass master as a mold and peeling the master stamper from the glass master to form the master stamper shown in FIGS. 4A to 4F described above. Step 2) From the master stamper 8, a mother stamper 9 is electroformed (in the embodiment, the same thickness) so that the thickness of the mother stamper is equal to or greater than 0.20 mm. The mother stamper forming step shown in FIGS. 4 (g) and 4 (h) for separating the mother stamper, and 3) electroforming a stamper 10 having a thickness of about 0.3 mm using the mother stamper 9 as a mold. This is the stamper forming step shown in FIGS. 4 (i) and 4 (j) for separating the stamper from the mother stamper.

A feature of the stamper manufacturing method of the present invention is that the thickness of the master stamper and the mother stamper is set to 0.01 to 0.01.
0.20 mm, and the thickness of the mother stamper 9 is set to 0.20 mm in the mother stamper forming step 2).
Is to be made thicker than the master stamper 8 within a range not exceeding The thickness of the mother stamper is preferably 1 to 1.5 times the thickness of the master stamper. As a result, as shown in FIG. 2 or FIG. 3, at the time of peeling both the mother stamper and the stamper forming process of the above 2) and 3), the soft release of the mother stamper can be achieved.

Therefore, FIGS. 4 (h) and 4 (j) also show a state in which the mother stamper is peeled off from the master stamper or the stamper. Accordingly, smooth separation is possible. Since the shape of the carried pits is also peeled off with elastic deformation around the pits, the pits do not collapse. The thickness of the master stamper and the mother stamper is 0.01 to 0.20 mm, particularly 0.08 to 0.18 mm
Is preferable. If it is less than 0.01 mm, there may be a problem with the strength of the mother stamper, and if it exceeds 0.20 mm, the flexibility may be reduced and the pit shape may be broken.

[0012]

As described above, according to the present invention, in the method for manufacturing a stamper, the thickness of the mother stamper and the master stamper is made thinner and the thickness of the mother stamper is made thicker than the thickness of the master stamper. The adhesive force at the time of peeling increases, and furthermore, the bending and curving of the master spunter enables smooth separation. improves.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a state in which a master stamper is separated from a glass master in a stamper manufacturing method according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a state in which a mother stamper is separated from a master stamper according to the present invention.

FIG. 3 is a schematic cross-sectional view showing a state in which a stamper is separated from a mother stamper of the present invention.

FIG. 4 is a schematic operation procedure diagram of a general stamper manufacturing method.

FIG. 5 is a schematic cross-sectional view showing how a mother stamper is peeled off from a conventional master stamper.

FIG. 6 is a partially enlarged cross-sectional schematic view of a master stamper peeling portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass master 2 Photoresist 3 Laser beam 4 Objective lens 5, 6 Unevenness corresponding to a groove or pit 7 Conductive film 8 Master stamper 9 Mother stamper 10 Stamper

Claims (4)

[Claims] 1. A master stamper forming step of electroforming a master stamper using a master as a mold and separating the master stamper from the glass master, and electroforming a mother stamper using the master stamper as a mold and separating the mother stamper from the master stamper. A stamper manufacturing method for producing a stamper having minute irregularities, including a mother stamper forming step and a stamper forming step of electroforming the stamper using the mother stamper as a mold and separating the stamper from the mother stamper, comprising: a master stamper and a mother stamper. Is 0.
A stamper manufacturing method, wherein the thickness of the mother stamper is equal to or greater than the thickness of the master stamper. 2. The mother stamper has a thickness of 0.08-0.
The method for manufacturing a stamper according to claim 1, wherein the diameter is 18 mm. 3. The thickness of the master stamper is 0.08 to
3. The method for manufacturing a stamper according to claim 1, wherein the diameter is 0.18 mm. 4. The method of manufacturing a stamper according to claim 1, wherein the stamper has minute irregularities corresponding to the information signal grooves or bits.