JP3015900B2 - Manufacturing method of optical disk memory - Google Patents

Description

The present invention relates to the structure of an optical disk memory.

[Conventional technology]

As a generally known method of manufacturing an optical disk memory, a photoresist is applied to a glass substrate,
A mastering step of exposing and developing an information pattern with a laser, and then producing a stamper. After injection molding the substrate material with a stamper, a reflective film is formed on the information pattern on the substrate, and then a resin (PMMA etc.) ) A protective film is formed, and the process is separated into a bonding replication process.

[Problems of the prior art]

As a method of applying a protective film on the reflective film, there is a method of applying a roll coater in a spin-coating or spraying area, but since both are performed in the air, a slight amount of moisture, oxygen, etc. is applied to the reflective film (Al). Therefore, it is expected that deterioration such as oxidation of the reflection film will occur in the long term. Further, although PMMA or the like is mainly used as a substrate of the optical disk memory, it has a hygroscopic property, and there is a concern that the reflection film (Al) may be deteriorated due to water diffusion for a long term. For this reason, there is an example in which Au or the like, which is unlikely to deteriorate such as oxygen, is used. However, since Au is very expensive, it raises the cost and is not suitable for mass production.

In addition, when the protective film is applied, the workability of handling and the like is poor because the reflective film is very soft.

〔Purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to improve the long-term reliability of an optical disk memory and prolong its life for the purpose of solving the above-mentioned conventional problems.

[Means to solve the problem]

According to the present invention, in order to achieve the above object, in an optical disc memory having a substrate, a reflective film and a protective film, a film containing carbon or carbon as a main component is formed in close contact with the reflective film.

In the present invention, before or after a reflective film is formed on an information recording pattern on a substrate by a sputtering method, a vapor deposition method, or the like, an adsorbed substance adheres to the reflective film by forming a film containing carbon or carbon as a main component in a vacuum. And prevents diffusion of water and the like from the substrate to the reflective film, thereby prolonging the life and improving long-term reliability. Further, by forming a film containing carbon or carbon as a main component after forming the reflection film, a large margin is given to the subsequent work.

In the present invention, carbon or a film containing carbon as a main component that is brought into close contact with the reflective film may be formed on one surface of the reflective film, or may be formed so as to scissor the reflective film.

 Hereinafter, the present invention will be described in detail with examples.

〔Example〕

FIG. 1 shows an outline of a plasma CVD apparatus for forming carbon or a film containing carbon as a main component of the present invention.

In the drawing, in the doping system (1), hydrogen or oxygen as an additive is converted from (2) to a hydrocarbon gas as a reactive gas such as methane or ethylene from (3).
Diborane (diluted with hydrogen) (4) as an I-valent impurity and ammonia or phosphorous as a V-valent impurity are introduced into a reaction system (8) from a nozzle (9) through a valve (6) and a flowmeter (7) from (5). Is done. Before reaching the nozzle, it is effective to apply microwave energy (10) to excite the reactive gas to activate it in advance.

The reaction system (8) includes a first electrode (11) and a second electrode (1
2) was provided. Electric energy is applied between the pair of electrodes (11) and (12) from a high-frequency power supply (13), a matching transformer (14), and a DC bias power supply (15) to generate plasma. An exhaust system (16) exhausts unnecessary gas through a pressure regulating valve (17), a turbo molecular pump (18), and a rotary pump (19).

The reactive gas has a pressure in the reaction space (20) of 0.00
An energy of 0.1 to 5 kW is applied by high frequency or direct current energy under 1 to 10 torr, typically 0.01 to 0.5 torr.

In particular, when the excitation source is at a frequency of 1 GHz or more, for example, at a frequency of 2.45 GHz, hydrogen is separated from the CH bond, and when the frequency source is at a frequency of 0.1 to 50 MHz, for example, at 13.56 MHz, CC is used.
Bond, decompose the C = C bond to form a -CC- bond,
Unpaired carbon atoms can collide with each other to form a covalent bond to form a structure locally having a stable diamond structure.

DC bias is -200 to 600V (effectively -400 to +40
0V). Because, when the DC bias is zero, the self-bias is -200V (the second electrode is grounded)
It is because it has.

The first electrode had a cooling means, and the temperature on the wave forming surface was kept at 250 to -100C.

FIG. 2 shows a single plate of the optical disk memory manufactured in the embodiment.

First, a substrate (21) (PMM) injection-molded by a stamper made through a mastering process by a known method.
A) Carbon or a coating containing carbon as a main component is formed by a parallel plate type plasma CVD shown in FIG.
A film was formed. (22) using a gas; CH ₄ 100SCCM + H ₂ 50SCCM reaction pressure; 10P _a RF electrode 120W film mainly containing following such carbon or a carbon This condition is obtained.

Vickers luminance: 2000 kg / mm or more Transmittance: 90% (550 mm) Pumping rate: 0% Density:> 2.25 g / cm ³ After that, a reflective film (23) of Al was formed by sputtering to about 2,000 Å, and further subjected to sputtering. A film (24) containing carbon or carbon as a main component was formed to a thickness of about 500 mm under the same conditions as the previous time. A protective film (25) was obtained by spraying a resin-based solvent-type paint and performing baking and curing. Thus, a single plate of the optical disk memory was manufactured. The protective film (2
5) The competitors were bonded together with an adhesive to form an optical disk memory. Further, each of the films (22), (23) and (24) is formed by a multi-chamber type apparatus, and is not exposed to the air during this time.

The optical disk memory made as above is stored at 80 ° C and RH
Fig. 3 shows the results of an accelerated test in a 95% constant temperature / humidity layer. The result that the long-term reliability was improved by the inclusion of carbon or a coating containing carbon as a main component was obtained. In the figure, the curve (2
6) shows the results of an acceleration test performed on an optical disk memory using carbon or a film containing carbon as a main component as a protective film, and curve (27) shows the results of an acceleration test performed on the current optical disk memory. is there.

In addition, good results were obtained even if the carbon or the coating containing carbon as the main component in (22) in FIG. 2 was omitted.

Furthermore, even if an external force such as scratching is applied with tweezers without a protective film made of a resin-based solvent-type paint, the hardness of the film containing carbon or carbon as a main component is high and the surface smoothness is high,
The reflective film was not damaged.

〔effect〕

In the present invention, it is possible to prevent adsorption of moisture or oxygen in the air to the reflective film during the formation of the protective film by forming a film containing carbon or carbon as a main component on the reflective film of the optical disk memory as described above. In addition, the deterioration of the reflection film due to the diffusion of water from the protection film to the reflection film can be prevented, and the long-term reliability of the optical disk memory can be greatly increased at low cost, and the workability can be greatly improved.

[Brief description of the drawings]

FIG. 1 shows an outline of an apparatus used for forming a film containing carbon or carbon as a main component of the present invention. FIG. 2 is a sectional view of a single plate (before bonding) of the optical disk memory. FIG. 3 is a diagram showing a change with time of the reflectance when the initial reflectance of the reflection film is set to 1. (21) Substrate (22) Carbon or carbon-based coating (23) Reflective film (Al) (24) Carbon or carbon-based coating (25) Resin-based protective film (26) Carbon or carbon Optical disk memory with a protective film consisting mainly of a coating (27) Current optical disk memory

Claims (1)

(57) [Claims] A first step of forming a first coating mainly composed of carbon or carbon on a substrate; a second step of forming a reflection film in contact with the first coating; A second carbon or carbon-based component in contact with the membrane
And a fourth step of forming a protective film on the second film. A method of manufacturing an optical disc memory, comprising: a first step to a third step; A method for manufacturing an optical disk memory, wherein the method is performed without exposing the optical disk to the atmosphere.