JPS637536A - Manufacture of optical disk recording medium - Google Patents

Abstract

PURPOSE:To uniformize the depth and the shape of a guide groove, and to improve an S/N, by applying a prescribed time of exposure to ultraviolet rays and baking processing, after forming a groove having a rectangular cross section by using an exposing and developing means, and forming the guide groove. CONSTITUTION:A photoresist film 1 is coated evenly on the surface of a glass plate 2 whose surface is cleaned, and next, the photoresist film 1 formed on the surface of the glass plate 2 is exposed in a spiral shape, or a concentric circle shape, by a condensed laser beam, and it is developed, then an exposed part is eliminated, and a rectangular groove 3 is formed. Next, an original board on which the rectangular groove 3 is formed, is heated in a baking furnace, etc. By the above heating, the fluidity is attached on the photoresist 1 after developing, and the corner part of the photoresist film 1 falls in drops, and flows in the rectangular groove 3, and an angle shaped photoresist film 4 is formed by embedding the rectangular groove 3, and a valley part forms a V-shape. In this way, surface coarseness is reduced, and the S/N can be improved, and also, since it is possible to uniformize the depth and the shape of the guide groove, the quality of a product can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing an optical disc recording medium.

In particular, it relates to improvements in the method of forming groups.

[Conventional technology]

When manufacturing an optical disk recording medium, a photoresist layer that is thicker than the depth of the required groups (guide grooves) is formed on the glass substrate when manufacturing the master disk.

The second photoresist layer is exposed to light in groups, and the exposed surface is developed to form guide grooves with a V-shaped cross section. Bits are formed within this group depending on the information content.

[Problem that the invention seeks to solve]

However, in the conventional method of manufacturing an optical disk recording medium, not only is it impossible to form guide grooves of uniform depth due to unevenness and variation in the development level.

This is because the side walls of the guide groove are also dissolved by the developer.

The side wall surface becomes rough. For this reason, there is a problem in that the tracking signal becomes non-uniform, leading to a decrease in S/N.

The present invention has been made in view of the above-mentioned actual state of the prior art,
The purpose is to provide a method for manufacturing an optical disc recording medium in which the depth and shape of the guide groove are made uniform, the roughness of the side walls is eliminated, and the S/N ratio is improved.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a method for manufacturing an optical disc recording medium including a master manufacturing process in which a guide groove for tracking is formed on a photoresist surface provided on a substrate using an exposure and developing means. A groove having a rectangular cross section is first formed using a developing means and then exposed to ultraviolet light for a predetermined time and subjected to baking treatment to form a guide groove of a predetermined shape.

[Effect]

According to the above means, the photoresist in the groove is melted by heating the groove formed in the rectangular cross section.

The upper edge collapses to form a mountain shape, and the 8th part has a V-shaped cross section, so by appropriately controlling the heating conditions, it is possible to have a guide groove that does not cause surface roughness or deterioration of S/N. A method for manufacturing an optical disc recording medium can be provided.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIGS. 1 and 2 are explanatory views showing the process of forming guide grooves in the present invention.

First, a photoresist film is uniformly applied to the surface of a glass plate whose surfaces have been cleaned.

Next, as shown in FIG. 1, the photoresist wA1 formed on the surface of the glass plate 2 is exposed in a spiral or concentric manner with a focused laser beam, and the exposed portion is removed by developing it. , forming a rectangular groove 3.

Next, the master disk on which the rectangular grooves 3 are formed is heated in a baking oven or the like. This heating causes the photoresist film 1 after development to
increases fluidity, causing the corners of the photoresist 111 to sag,
By flowing into the rectangular groove 3, the inside of the rectangular groove 3 is filled as shown in FIG. 2, and a mountain-shaped photoresist film 4 is formed, and the valley portion becomes a figure 7 shape. At this time, the surface roughness caused by development almost disappears. Therefore, there is no reduction in S/N.

Here, a specific example will be described based on the cross-sectional views of FIGS. 3 and 4.

A positive photoresist film 6 containing phenol novolak as a main component is deposited on a glass plate 5 whose surface has been cleaned to a thickness of 25.
Spin coating on 00 people.

Next, after performing pre-beta at 80℃ for 30 minutes,
The surface of the photoresist film 6 is exposed in a spiral manner (1.6 μm pitch) using an Ar laser (wavelength: 4579λ).Furthermore, spin development is performed using an alkaline developer (MP De, R Belotsuba). Spin development is performed by rotating the master disk and letting the developer flow down from above.When the development reaches a predetermined level, the development is stopped and washed with water, thereby forming the grooves 7 shown in Fig. 3. You can get the master disc.

Next, f! shown in FIG. Place the board in the baking oven.

Heat at 150"C for 10 minutes. By this heating.

As shown in FIG. 4, the photoresist film 6 flows into the groove 7, and the depth of the valley becomes 0.037+71. Further, the thickness of the photoresist film 8 after the heat treatment is 1600 mm.

In this baking process, if the master is irradiated with ultraviolet rays, fluidization of the photoresist film 6 can be promoted as shown in FIG. 5.

The final product, an optical disc recording medium, is produced through the following steps. First, nickel vapor deposition and nickel plating are sequentially applied to the surface of the master resist film made as described above, and a laminate of the nickel vapor deposited film and nickel plating film is gdJIIlled from the surface of the resist film to form an uneven pattern. A standber is produced which is inverted from the above master disc. Next, using the standby as a master mold, a disk substrate having a concavo-convex pattern reversed from that of the standby (same as the master) is manufactured. Finally, a recording layer is formed on the uneven pattern transfer surface of the disk substrate to obtain a desired optical disk recording medium. Examples of recording materials forming the recording layer include low melting point alloys, magneto-optical recording materials, organic dyes, etc.
Any heat mode recording material can be used.

In addition, in the type of optical disc recording medium that requires preformatting such as address bits and clock pits, the preformat is recorded on the recording layer after the recording layer is formed.

〔Effect of the invention〕

As explained above, according to the method of manufacturing an optical disc recording medium of the present invention, the S/N is reduced by reducing surface roughness.
In addition, since the depth shape of the guide groove can be made uniform, quality can be improved. Furthermore, process control can be simplified.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing the main parts of the manufacturing process of an optical disc master according to the present invention, FIGS. 3 and 4 are explanatory diagrams showing a specific embodiment of the present invention, and FIG. FIG. 3 is a flatness characteristic diagram with pattern deformation with respect to beta temperature in FIG. 1...Photoresist film, 2...Glass plate, 3...Rectangular groove, 4...Photoresist film after heating Fig. 1 Fig. 2

Claims (1)

[Claims] In a method for manufacturing an optical disk recording medium, which includes a master manufacturing process of forming a guide groove for tracking on a photoresist surface provided on a substrate using exposure and development means, grooves having a rectangular cross section are formed using exposure and development means. 1. A method of manufacturing an optical disc recording medium, which comprises forming guide grooves by exposing them to ultraviolet light for a predetermined period of time and baking them.