JPS62298951A - Production of optical disk substrate - Google Patents

Abstract

PURPOSE:To remove the uncured resin component remaining on a transfer surface and to improve the quality of a thin magnetic recording medium film by subjecting the surface of a transferred photosetting reaction resin to a cleaning treatment by an org. solvent. CONSTITUTION:A substrate 11 with which the transfer of guide grooves by applying the curing reaction of the photosetting resin is completed is mounted to a turn table of a spin coater. The substrate is then kept rotated at about 300rpm and the ketone solvent heated to about 60 deg.C, for example, solvent such as methyl ethyl ketone or acetone is dropped dividedly 3-4 times onto the substrate to remove the unreacted resin component remaining on the surface of the photosetting resin layer. After the unreacted resin component is removed, rinsing by distilled water is executed and thereafter the substrate is dried on the turn table for about 10min. The unreacted resin in the resin layer 15 transferred with the information of a die pattern is removed and the CN ratio and noise level of the recording medium layer for optical information are remarkably improved.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In the production of an optical disk substrate used for recording and reproducing optical information, mold pattern information forming a standby master is stamped on a photocuring reaction resin layer. The quality (carrier-to-noise ratio) of the magneto-optical recording medium is improved by removing the remaining unreacted photocuring resin on the transfer surface of the track plan or groove.

[Industrial application field]

The present invention relates to a method of manufacturing an optical disk substrate provided with an optical recording or magneto-optical recording medium.

Substrates that record high-density information using laser light have a large storage capacity, and have been put into practical use as optical disk memories that can record information or reproduce recorded information without contacting an optical or magneto-optical head.

The substrate used to record such optical information was developed by Hatsutomo Kezo to detect and control the trunk position relative to the opto-magnetic nozzle of the optical disk. Track guide grooves with minute irregularities and address vibrations are considered essential for the purpose of 3D.

It is formed by stamp transfer from a mold pattern via a photocurable resin layer.

Subsequently, a magneto-optical recording medium film is formed on the entire surface of the stamp-transferred resin transfer surface by the Svata method. cleaning with a solvent.

[Conventional technology]

FIG. 1 is a cross-sectional view of a completed optical disc substrate, and FIG. 2 is a basic configuration diagram (cross-sectional view) for transferring mold pattern information.

In the figure, reference numeral 10 denotes a mold or a transfer mold, and the transfer mold 10 consists of a carrier disk 16 with a protruding axial center portion and a mold pattern information part 17 adhered to the surface of the disk 16.

Reference numeral 11 denotes a substrate on which the pattern information section 17 is transferred, which is placed through a spreading layer of photocuring reaction resin, and 13 is a photocuring reaction resin, such as an acrylic resin, which is spread on the pattern information section 17 in advance. be.

The mold pattern information section 17 is made of a nickel (Ni) electroformed film, and a concentric or spiral track guide groove 12 is engraved on its surface using photolithography.

However, the surface of the guide groove 12 of the nickel electroformed film is the mold 10 of the transfer resin layer 13 that undergoes photocuring reaction aging after transfer.
In order to improve release from the mold (mold releasability), oxidation treatment by plasma sputtering or coating treatment with a polyethylene film having a thickness of about 0.01 μm is performed.

During pattern transfer, the substrate 11 centered with respect to the mold 10 is brought into pressure contact with the mold by a pressure mechanism (not shown) of a standby device.

Also, ultraviolet rays are placed on the back of the board 11! The photocuring reaction resin layer 13 is cured by A14. After the resin layer 13 is cured and matured, the substrate 11 is peeled off from the mold 10.

An optical disk substrate 21 having a resin transfer layer 15 as shown in FIG. 1 is produced.

Subsequently, a magnetic alloy film made of a terbium-cobalt-iron alloy is deposited over the entire surface of the substrate 21 having the peeled resin transfer layer 15, thereby forming an optical information recording medium film.

[Problem that the invention seeks to solve]

There is no problem with the mold pattern information (resin transfer N15 of U) on which the photocuring reaction resin 2, for example, an epoxy resin is spread, as long as the curing reaction of the resin is completed by ultraviolet irradiation.

However, according to the study results of the present inventors, when the resin transfer layer 15 of the recording medium base layer was inspected by, for example, infrared absorption spectrometry, it was found that uncured resin components remained, and the transfer surface due to this remained. Deposition of a subsequent magnetic alloy film under such conditions is problematic.

Means for Solving Problem C] After the trunk guide groove is transferred, the mold pattern information is stamped onto the optical disk substrate (hereinafter also referred to as the substrate) by irradiating the pressure-adhesive layer of the photo-curing reaction resin with light.

The above-mentioned problems have been solved by the method of manufacturing an optical disc substrate of the present invention, in which the surface of the transferred photocuring reaction resin is cleaned with a heated organic solvent.

[Effect]

By removing the uncured resin component remaining on the transfer surface with, for example, a ketone-based W solvent (temperature of about 60°C) without dissolving the pattern information on which the trunk guide groove etc. have been transferred, subsequent steps can be carried out. The quality of the optical information recording medium magnetic thin film deposited in this manner is improved.

As a measure of quality improvement, for example, magnetic thin film bottom H'JJ
As seen from the carrier-to-noise ratio of the recording quality at
n) It is obvious that the signal CN ratio is improved by 6 dB.

〔Example〕

Hereinafter, a method of cleaning the resin transfer surface stamped with mold pattern information such as guide grooves will be explained.

The substrate, on which the guide groove has been transferred using the curing reaction of the photocurable resin, is mounted on the rotary table of the spin coater. And as a rotation state of about 30 ORPM.

Add to this a ketone solvent 5 heated to about 60°C, such as methyl ethyl ketone, or acetone.
The unreacted resin component remaining on the surface of the photocured resin layer, which will become the guide groove transfer, is removed by dropping 3 to 4 times on the substrate.

After removing the unreacted resin components, the product is rinsed with distilled water and then dried on a rotating table for about 10 minutes.

A chlorinated solvent 3, such as chloroform, is used in place of the ketone solvent used in the description of the examples.

Tetrahydrofuran, methylene chloride and carbon tetrachloride may also be used.

The carrier-to-noise ratio (CN ratio) of a substrate using the above cleaning method and a conventional substrate with the same structure that is not cleaned, on which a magnetic thin film is formed as an optical information recording medium and a 0.5 MHz signal is recorded thereon. ) and noise level (N
When comparing L), the substrate of the present invention: CN = 43
dB NL = -40dB Conventional board: CN
= 37 dB NL = -36 dB quality improvement of the optical recording medium layer was confirmed.

〔Effect of the invention〕

As is clear from the above description, according to the method for manufacturing an optical disk substrate of the present invention, by removing unreacted resin in the transfer resin layer of mold pattern information, the CN ratio of the optical information recording medium layer and Noise level is noticeably improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the optical disc substrate after transfer. FIG. 2 is a sectional view of the basic configuration for transferring mold pattern information. In the figure, 10 is a transfer mold (mold). 11 is a disk board. and 15 is a resin transfer layer.

Claims (1)

[Claims] After the track guide grooves for stamping the mold pattern information on the optical disc substrate are transferred by irradiating the pressure spreading layer of the photocuring reaction resin with light, an organic solvent is heated on the surface of the photocuring reaction resin of the transferred optical disk substrate. 1. A method of manufacturing an optical disk substrate, the method comprising cleaning the optical disk substrate by: