JPH0332825A - Manufacture of stamper - Google Patents

Abstract

PURPOSE:To reduce drastically breaking of a pit form, by futher thinning a board thickness of a mother stamper respectively than those of a master stamper and stampers. CONSTITUTION:A master stamper 8 is electroformed by making use of a glass matrix as a mold, which is peeled off. A mother stamper 9 is electroformed by making use of the master stamper 8 as the mold, which is peeled off. A stamper 10 is electroformed by making use of the mother stamper 9 as the mold and the stamper is peeled off from the master stamper. In other words, at the time of peeling, soft peeling of the mother stamper can be attained and breaking of a pit form vanishes by making a board thickness of the mother stamper 9 thinner respectively than those of the master stamper 8 and stamper 10.

Description

Detailed Description of the Invention Technical Field The present invention relates to a stamper carrying circular bits used when copying a recording medium having a recording layer carrying minute irregularities (hereinafter referred to as bits) from a master, such as an optical disc. Regarding the manufacturing method.

BACKGROUND ART Conventionally, a stamper manufacturing method as shown in FIG. 2 has been known for manufacturing a stamper for duplicating compact discs (hereinafter referred to as CDs).

First, as shown in FIG. 2, a liquid photoresist is uniformly applied to the surface of a flat glass disk 1 using a spin code method or the like, and is dried to form a thin film of photoresist 2.

Next, as shown in FIG. 2+b>, the glass disk 1 carrying the photoresist 2 is mounted on a so-called cutting device, and while the glass disk 1 is rotated, a laser beam 3 flickering in response to a predetermined signal is directed toward the objective. The photoresist 2 on the rotating glass disk 1 is irradiated through the lens 4. In this way, a spiral or concentric pit array carrying a predetermined signal is formed on the odd resist 2 as a latent image.

In this way, after developing the glass disk 1 with the photoresist 2, a glass master disk having a row of pits 5 is created, as shown in FIG. 2(C).

Next, as shown in Figure 2, conductive material ff1ll17 of silver, nickel, etc. is formed on the photoresist 2 of the glass disk 1 by sputtering or the like to make the pit surface of the glass master conductive.

Next, as shown in FIG. 2, the glass disk 1 having the conductive film 7 is immersed in an electroforming tank, and a master stamper 8 made of nickel with a thickness of about 0.3 mm is placed on the conductive film 7. Cast.

Next, as shown in FIG. 2 (h), the electroformed master stamper 8 is peeled off from the glass disk 1, the photoresist 2 remaining on the surface of the master stamper 8 is cleaned, and the master stamper 8 made of nickel is removed. get.

Next, as shown in FIG. 2<9), the master stamper 8 is immersed in an electroforming bath, and a mother stamper 9 made of nickel having a thickness of about 04 mm is electroformed on the bit surface of the master stamper 8.

Next, as shown in Figure 2, the electroformed mother stamper 9 is peeled off from the master stamper 8 to obtain a nickel mother stamper 9. Several mother stampers 9 can be obtained by repeating these steps.

Next, as shown in FIG. 2 (i+), the mother stamper 9 is immersed in an electroforming tank to form a film with a thickness of about 0.
A stamper 10 made of 3II11 nickel is electroformed.

Finally, as shown in FIG. 2, the electroformed stamper 10 is peeled off from the mother stamper 9 to obtain a nickel stamper 10. By repeating these steps, several dozen stampers 10 can be obtained.

When such a manufacturing method of the stamper 10 is applied to the manufacturing of a stamper for an optical disk using the sample servo method (hereinafter referred to as the SS method), the stamper 10 for an optical disk that creates a large number of pits on the signal bearing surface of a CD etc. However, the S produced from the stamper 10 did not cause any problem.
A problem arises in that the reproduced waveform of the S-system optical disc is disturbed.

In other words, as a result of investigating the cause of the disturbance in the reproduced waveform mentioned above,
In the stamper 10 of the SS system optical disc, the stamper 10
Electron micrographs revealed that the head of the pit formed on top had collapsed, as if it had been scraped off.

This pit collapse is caused by the master stamper 8 attached after electroforming as shown in Figure 2 during the manufacturing process and as shown in Figure 2 (j).
Also, when the mother stamper 9 and the mother stamper 9 and the stamper 10 are peeled off, the pits of each other are caused by surface displacement in the direction shown in FIG.
As shown in the figure, the pits are likely to become distorted and collapse.

On the other hand, in the case of a stamper such as a CD in which the signal bearing surface has many irregularities due to pits or pre-groups, the disks are in strong contact with each other, and surface displacement is suppressed.

However, in SS system optical discs, there is no pre-group and the number of pre-formed pits is extremely small, so the adhesion between the discs is weak, and when the discs are peeled off, surface displacement occurs on their surfaces, causing pits. It will collapse.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stamper manufacturing method that can manufacture a stamper with less pit collapse.

The stamper manufacturing method of the present invention is a method for manufacturing a stamper having minute irregularities, and includes a master stamper forming step of electroforming a master stamper using a glass master as a mold and peeling the master stamper from the glass master; Electroforming a mother stamper as a mold,
The process includes a mother stamper forming process in which the mother stamper is peeled off from the master stamper, and a stamper forming process in which the stamper is electroformed using the mother stamper as a mold and the stamper is peeled off from the mother stamper. A special embodiment characterized in that the thickness of the plate is thinner than that of . Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The stamper manufacturing method of this embodiment includes the following steps, almost the same as the conventional method. That is, l) the master stamper forming process shown in the above-mentioned Fig. 2 (al to Fig. 2+f+) in which the film thickness is determined using the glass master disc as a mold, the master stamper 8 of 3 tars is electroformed, and the master stamper is peeled from the glass master disc. , 2) The mother stamper forming process shown in FIG. 2 and FIG. 3) Using the mother stamper 9 as a mold, electroform the stamper 10 with a film thickness of about 0.3a+e, and peel off the stamper from the mother stamper. Stamper formation as shown in FIGS. 2+b and 2+j+ above. It is a process.

The feature of the stamper manufacturing method of this embodiment is that in the mother stamper forming step 2), the thickness of the mother stamper 9 is made thinner than the thickness of each of the master stamper 8 and the stamper 10. As a result, as shown in FIG. 1, flexible peeling of the mother stamper can be achieved at the time of peeling off the mother stamper and the stamper in the image forming process of 2) and 3) above.

Therefore, although the mother stamper is peeled off from the master stamper or the stamper in Figure 2 (Mountain) and Figure 2 (j), the mother stamper is thinner and is stuck to the stamper. Smooth separation is possible with bending and curving from the disc. The shape of the supported pit is also peeled off while the surrounding area undergoes elastic deformation, so the pit does not collapse. The thickness of this mother stamper is preferably in the range of 0.08 to 0.18+gs.

This is because if the thickness of the mother stamper is less than 0.08mm, the strength of the mother stamper cannot be maintained, and the thickness of the mother stamper is 0.1f.
This is because if it exceeds 1 mm, the bit shape will collapse.

Effects of the Invention As described above, according to the present invention, since the thickness of the mother stamper is made thinner than the thickness of each of the master stamper and the stamper during the stamper manufacturing method, the adhesion strength when peeling them is increased. Furthermore, the bending and curving of the master stamper enables smooth separation, and therefore, the deformation of the pit shapes of the master stamper, mother stamper, and stamper is greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing how a mother stamper is peeled off from a master stamper or a stamper in a stamper manufacturing method according to the present invention, FIG. 2 is a schematic cross-sectional view showing a stamper manufacturing method, and FIG. FIG. 4 is a schematic cross-sectional view showing how the stamper is peeled off, and FIG. 4 is a partially enlarged cross-sectional view of the peeled part of the master stamper. Explanation of symbols of main parts 1...Glass disk 2...Photoresist 3...Laser beam 4...Objective lens 5... Pit 7... Conductive film 8... Master stamper 9... Mother stamper 0... Stamper

Claims (1)

[Scope of Claims] A stamper manufacturing method for creating a stamper having minute irregularities, comprising: a master stamper forming step of electroforming a master stamper using a glass master as a mold, and peeling off the master stamper from the glass master; a mother stamper forming step of electroforming a mother stamper using a master stamper as a mold and peeling off the mother stamper from the master stamper; and a stamper forming step of electroforming a stamper using the mother stamper as a mold and peeling off the stamper from the mother stamper. a forming step, and the manufacturing method is characterized in that the thickness of the mother stamper is made thinner than the thickness of each of the master stamper and the stamper.