JPS58224450A - Manufacture of original disc for duplicating information medium - Google Patents

Abstract

PURPOSE:To obtain an original disc of an optical disc high in quality, by forming a specified org. substance layer on a base, forming a metallic layer on this layer, forming holes corresponding to information bits with light beams, and etching the org. substance layer through these holes to form information bits. CONSTITUTION:A photoresist is applied to a base 1 made of glass disc or the like by coating or copper phthalocyanine is applied by vapor deposition to form an org. substance layer 2, and a layer 3 is formed on this layer 2 by vapor- depositing a metal, such as Te, Bi, or Al, or such an alloy. Then, holes (a) corresponding to information bits are formed by radiating laser beams on the layer 3, and the disclosed parts of the layer 2 is etched with plasma by masking the layer 2 with the layer 3 to form the information bits (b) through the layer 2. Thereafter, all of them are dipped into a dilute nitric acid soln. to dissolve away the layer 3 to obtain a superior original disc for duplicating optical discs for use in video recorders, etc., having constant depth of the recesses with high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field of the invention The present invention relates to &! Regarding the optical tisf technology as technology 1J, to be more specific, for example, it is possible to use a large amount of t1v information media such as audio and video CI) original disks.
This invention relates to a method for manufacturing a K-sized master disc for S.

(2)) Prior Art and Problems Conventionally, photoresists have not been mainly used to manufacture master discs for optical discs. This conventional master manufacturing method first places a film resist on a glass substrate, irradiates it with an ntcft beam that is focused and intensity-modulated by information while rotating it, and then The process consists of developing a photoresist master 2 with unevenness by developing with a developer. Original disc! ll
For example, the W machine to be manufactured is as follows.

Gold is applied to the master disk created as described above by electroless plating, and two-layer electroforming is performed. Using the obtained f1Jc nickel stambar, a plastic snack mold was made in the same manner as for making a record, aluminum was deposited on top of the mold by reflective AT, and a plastic protective film was further applied. However, in the case where the master is manufactured as described above, the cause is due to the photoresist coating method, so Φ is
A drawback is that the depths of the four parts of the ft photoresist, T, that is, the parts corresponding to the information bits, are not uniform.

This drawback has not yet been overcome, even though attempts have been made to improve the photoresist coating method and to discover new materials to replace it. In addition, the depth of this G'J ↓ four parts is usually not a bit,
This isn't working either. In addition, since the light reflectance of photoresist is extremely low, at around 4 cm, the reflected light for so-called focus servo, which accurately focuses a focused light beam on the resist during writing, is weak. There is a problem (3) in which the servo cannot be kept stable. For example, if there are variations in bit depth, 7
8 raw signal cD8/N is caused by the ty
c. If the focus servo is not stable, the spot diameter of the writing light spot will fluctuate, making the bit diameter and depth unstable, and the S/N of the reproduced signal will decrease.
'to be guided.

(3) The purpose of jealousy is the above-mentioned trap ↓ Considering the shortcomings of the conventional master production method%
The depth of the obtained master is constant and can be increased.
It would be desirable to provide a method for reproducibly producing an improved n7 master disc having a high reflectivity. An object of the present invention is to provide such a master recording method 2.

(4) Inventive Power Structure The present inventors have now achieved the above objective by performing the following steps: 1-machine on a substrate! forming a metal layer above the layer, and selectively removing a portion of the metal layer with focused light to form holes corresponding to information bits. (4) removing the organic material layer that can be exposed through the hole by plasma etching, and removing the remaining metal N;
forming an information medium duplication master comprising a substrate and an organic material layer having recesses corresponding to the information bits by removing II. I discovered that it is possible to achieve this.

According to a preferred embodiment of the method of the present invention, it is preferable to interpose a stabilizing layer, such as a carbon thin film CD, between the material layer and the metal layer. This is because the presence of the organic material stabilizing layer makes it possible to avoid deformation of the organic material layer due to the heat generated when holes are made in the metal layer formed above it.

(5) Invention (LJ Examples) Next, the present invention will be explained with reference to the attached drawings.

FIG. 1 shows the step of forming an organic material layer 2 and a metal layer 3 above a substrate l as the first R stage of the manufacturing process.

As the substrate 1, for example, in addition to a glass substrate commonly used in this technical field, a plastic substrate made of acrylic resin, a metal substrate, etc. can be used. An organic material layer 2 is formed above the substrate 1 which has been smoothed using this platform. The organic substances used here are
There is no particular limitation as long as it can be easily etched and satisfies the conditions as a master. For example, almost any organic photoresist commonly used in the art, such as Azla50J, can be used.

P-2 can be formed using a spin code method from a solution containing a photoresist. Furthermore, for a platform where a more constant film thickness is to be obtained, it is preferable to form this layer 2 by a vapor deposition method or a vapor phase growth method.As an organic material suitable for this purpose, for example, copper is used. Examples include metal phthalocyanines such as tetracyanine and lead phthalocyanine, styrene, polymethyl methacrylate, and others. The metal layer 3 is formed above the organic material layer 2. The thickness of the organic material layer 2 is generally -400 to +40 OA. Useful metals include, for example, Te, Bi, See As
Metals or metals such as (7) & gold or Aノ, A
u.

A base metal such as Cr*T i , S n , P b or the like can be used. Such a metal is deposited over the organic material layer 2 according to conventional thin film formation techniques, such as vacuum evaporation. Generally, the thickness of the metal layer 3 is preferably about 100AG.

According to the present invention, although not shown, a stabilizing layer may be provided between the organic material layer 2 and the metal layer 3, for example. For example, when interposing an amorphous film of carbon,
It is possible to form a layer by vapor deposition.

FIG. 2 shows the step of selectively removing a portion of the metal layer 3 with a focused light beam (7), for example a laser beam, to form holes a corresponding to information bits. The bulge in the metal layer 3 around the hole a indicates that metal evaporated during drilling the hole with laser light is attached to the surrounding area. When drilling holes.

While rotating the substrate l at 450-1800 rpm,
For example, a predetermined position is irradiated with a laser beam similar to that of an Ar laser beam. The light intensity of the laser light can be modulated according to the information to be recorded.

Next, the organic material layer 2 that can be exposed through the hole a is removed by plasma etching process I7, as shown in FIG.
becomes. Plasma etching can be carried out according to a conventional method using, for example, a parallel plate plasma etching apparatus and introducing a gas such as 0□ or CF'4.

Finally, as shown in FIG. 4, the metal layer 3 remaining on the organic material layer 2 is removed. In this removal process, care must be taken not to damage the organic material layer 2 of the etching VK.1 Usually, the residual metal layer 3 is removed by immersing it in a weak acid solution such as dilute nitric acid (8). is preferred. Plasma etching can also be used if necessary. When the removal of the metal layer is completed, a master for information medium duplication is obtained, which consists of a substrate 1 and an organic material layer 2 having a recess corresponding to the information focus.

Next, the present invention will be explained with reference to examples.

Example 1; Outer diameter 356 mm, inner diameter 20 mm and wall thickness 61 m (/-) 7 Otoregis T・tatUl [50
Spin coded from 0 to 1400A. On this resist film, a tellurium (Te)'E film having a thickness of 100 Å was vacuum deposited. After the vapor deposition was completed, an Ar laser beam was focused to a diameter of 0.8 m+ and irradiated onto the substrate while rotating the substrate at 1800 rpm. The Te film in the irradiated area was dissolved, creating holes corresponding to the information bits. In this case, it was sufficient that the output of the laser beam was approximately 8 mW or more at a position 150+u from the center of the disk. After completing the hole drilling, place the substrate in a parallel plate type plasma etching device [1! Then, the resist film was etched through the hole (window) of the Te film formed previously. The introduced gas was 0□, and the degree of vacuum was 50 m Torr. After removing the exposed resist film by etching, the substrate was immersed in a dilute nitric acid solution to dissolve and remove the remaining TeIIK. The depth of the formed recess corresponding to the information bit was constant. Furthermore, in this example, since the reflectance of the surface of the Te film is 30-, one reflected light is used to correct the position of the objective lens. What is called focus servo is easy to do.

Example j2: Repeat the method described in Example 1 above, but with the exception of two
1 Copper phthalocyanine was used in place of the photoresist AZ1350J, and an amorphous carbon (Q) film was evaporated to a thickness of 10 to 50A between the steel phthalocyanine film and the Te film, which were formed by vacuum evaporation. The carbon thin film was removed by plasma etching using 0□. In the case of 0J in this example as well, four parts having a uniform depth were obtained as in Example 1. Furthermore, a trap with a carbon thin film interposed therebetween was obtained. Therefore, it was possible to avoid surface deformation of the steel phthalocyanine film due to heating.

(6) Effects of the Invention According to the present invention, it is possible to manufacture with good reproducibility a master disk having irregularities corresponding to the information bits and having a constant depth in its four parts. Furthermore, according to the present invention, the organic material layer does not need to have particular photosensitivity, so it is possible to manufacture the master disc under daylight. Furthermore, the selection range of organic substances and the range of their applications (film forming methods) are wide-ranging. This means that the film thickness can be easily controlled and that highly uniform [ can be obtained. Therefore, the IC can make the height of the unevenness constant and reduce the variation, making it possible to manufacture a high-quality master disc.

[Brief explanation of the drawing]

The drawings are cross-sectional views showing step by step the process of manufacturing a master according to the present invention. FIG. 1 shows the steps of forming an organic material layer and a metal layer; FIG. 2 shows the steps of forming holes in the metal layer The third factor is the etching step of the cool material layer: (1
1) FIG. 4 schematically shows the sleeve and metal layer removal steps. In the figure (/, 31 is the substrate, 2iIN mechanical material layer, 3 is the metal layer, and the a and bVi information bit corresponding parts. Patent applicant Fujitsu Limited Patent application agent Akira Ikuki Patent attorney Kazu Nishidate Patent Attorney Office 1) Male Patent Attorney Akiyuki Yamaguchi (12) Ku Ku Descendant Awa Ku Ku Ku ('N') 4 Eyes
Kyo

Claims (1)

[Claims] 1. A method for manufacturing a master for information medium reproduction, which includes the following steps: forming an organic material layer on a substrate, and further forming a metal layer above this layer. Part 2 of the metal 1-2 is focused and the LC source beam I is selectively etched away to form a hole corresponding to the information bit.2 The target organic material layer exposed through the hole is subjected to plasma etching. F removal paste and residual @Kangen 1
- A master disk for duplicating information media consisting of a substrate and an organic material layer containing recesses corresponding to information bits? 1. A method for producing an information medium duplicating master, comprising: forming a master disk. 2. A stabilizing layer 2 between the organic material layer and the metal layer.
5. The manufacturing method according to claim 1, number C. 3. The stabilizing layer is a carbon thin film. A manufacturing method according to claim 2.