JPH07109667B2 - Method for manufacturing optical disc stamper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an optical disc stamper, and more particularly to improvement in electric plating applied after formation of a conductive film.

[Conventional technology]

FIGS. 1A to 1G are explanatory views showing an example of a manufacturing process of an optical disk.

First, as shown in FIG. 1 (a), a photoresist 11 is uniformly applied to the surface of a glass substrate 10 which is polished to a mirror finish.

Then, as shown in FIG. 1B, the photoresist 11 is irradiated with the laser beam 12 modulated by the information signal to be recorded.

Then, as shown in FIG. 1 (c), the substrate 10 is subjected to a phenomenon by a photographic means, and a laser beam irradiated portion of the photoresist 11 is converted into a pit or tracking signal having an array corresponding to an information signal. Form corresponding groups 13.

Then, as shown in FIG. 1 (d), the recorded master 14 on which the information signals are recorded in the form of the pits 13 as described above.
Conductive film is formed on the recording surface by vacuum deposition or sputtering.
Forming fifteen.

Then, as shown in FIG. 1 (e), nickel is electrically plated to a thickness of about 0.2 mm using the conductive film 15 as a cathode.
The nickel master 16 is formed.

Then, as shown in FIG. 1 (f), the recorded master 14 is peeled off from the nickel master 10 to obtain a recorded master.
Take out the nickel master 16 in which the unevenness of the signal is opposite to that of 14.

Finally, as shown in FIG. 1 (g), a resin material is molded using this nickel master 16 as a mold (stamper), and an optical disk 17 having the same unevenness as the pits 13 of the recorded master 14 is duplicated. To do.

Conventionally, the film thickness of the conductive film formed in the step of FIG. 1 (d) is set to 500 to 1500Å. Due to such a thin film thickness, contact breakage may occur when a large current is passed at the start of electric plating for forming a nickel master. Therefore, conventionally, the current density at the start of plating is 0.1 A / d
A method of suppressing the current to about m ² and increasing the current linearly or stepwise with the passage of time is adopted.

[Problems to be solved by the invention]

However, in the conventional electric plating method of the optical disc stamper, since the current density at the start of the plating is low, the plating film formation rate becomes slow, and the plating solution at the vapor deposition film-resist interface during plating is slowed down. May penetrate and cause foam-like or spot-like stamper defects.

The present invention has been made in view of the above circumstances of the prior art, and an object thereof is to prevent the occurrence of defects on the surface of the stamper, improve the yield of the stamper, and improve the quality of the optical disk stamper. To provide.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention includes an optical disk including a step of forming a conductive film on a master having a groove formed on a glass substrate through a predetermined process, and applying a plating layer using the conductive film as an electrode. In the stamper manufacturing method, the current density at the start of plating is set within a range that does not cause defects on the stamper surface.

[Action]

According to the above means, by setting the current density at the start of energization to a value within a predetermined range, it is possible to prevent permeation of the plating solution into the vapor deposition film-resist interface during plating and to prevent stamper defects. It is possible to provide an electric plating method for an optical disc stamper that does not occur.

〔Example〕

Hereinafter, the method for electrically attaching the optical disc stamper according to the present invention will be described in detail.

First, a positive resist is uniformly applied to a glass substrate to a thickness of 1500 Å. Then, a relief pattern corresponding to the information signal is formed on the resist layer by using an argon (Ar) gas laser to prepare a master.

This master is baked in an atmosphere at a temperature of 120 ° C. for 60 minutes, and then a 1000 Å nickel (Ni) conductive film is formed by a vacuum evaporation method.

Multiple masters prepared as described above were prepared, immersed in a sulfamic acid nickel plating bath, and nickel plating was performed by setting various initial current densities in this state, and the results shown in the table below were obtained. was gotten.

As is clear from this result, the initial current density of plating is 0.
If it is 2 A / dm ² or less, a stamper defect occurs, and if it is 1.0 A / dm ² or more, the conductive film is likely to be melted by resistance heating, and contact breakage occurs to make the plating process impossible.

Therefore, the current density at the start of plating is 0.2-
By setting it within the range of 1.0 A / dm ² , it is possible to increase the plating film formation rate and prevent penetration of the plating solution into the vapor deposition film-resist interface of the plating solution.

〔The invention's effect〕

As described above, according to the present invention, the initial current density at the time of plating is set within the range where the stamper defect does not occur, so that the penetration of the plating solution into the resist film is eliminated and the stamper defect is not generated. . As a result, the quality and yield of the stamper can be improved.

[Brief description of drawings]

FIGS. 1A to 1G are explanatory views showing an example of a manufacturing process of an optical disk. 10 …… Glass substrate, 11 …… Photoresist, 13 …… Groove, 14 …… Master disk, 15 …… Nickel plating, 16 …… Nickel master.

Claims (2)

[Claims] 1. An electric plating method for an optical disk stamper, which comprises the steps of forming a conductive film on a master having a concavo-convex pattern formed on a glass substrate through a predetermined process, and forming a plating layer using the conductive film as an electrode. 2. A method for manufacturing an optical disc stamper, wherein the current density at the start of plating is set within a range that does not cause defects on the stamper surface. 2. The method for manufacturing an optical disk stamper according to claim 1, wherein the current density is 0.2 A / dm ^{2 to} 1.0 A / dm ² .