JPH02145384A - Forming method for optical recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an optical recording medium that performs at least recording or reproduction using light.

[Prior Art] Conventionally, as a method for producing an optical recording medium, a method is known in which a thin film is produced by sputtering or the like based on a base material called a target.

A careful study of the properties of the thin films produced in this way has revealed that even trace amounts of oxygen and moisture can have a very large effect on the properties.

For example, even if 1% or less of oxygen exists in the rare earth-transition metal alloy film, which is widely used as a luminous n-air recording medium, the durability characteristics are adversely affected. In addition, the telephone film produced by sputtering, which is known as the i-retaining film for magneto-optical recording, is also sensitive to its optical properties and the diffusion of oxygen into the rare earth-transition metal alloy that is the recording film in contact with it. The presence of oxygen and moisture also reduces durability.

These are the effects of extremely small amounts of oxygen and moisture, but if the content exceeds a few percent, recording and reproduction will also be affected as substrate properties.

Next, a method commonly used as a countermeasure for such problems will be explained.

First, at a target manufacturer, a target vacuum-sealed in a container made of polyvinyl or the like in an argon or nitrogen atmosphere is applied to a copper substrate called a backing plate using a brazing agent or the like in as short a time as possible.

Next, this is set directly by breaking the vacuum in the film forming chamber or from the pre-film forming chamber.

I try to do these as quickly as possible, but
Even so, if the target is polycrystalline, the grain boundaries will be oxidized, and if the target is a sintered body, the areas in contact with the pores will be oxidized to a depth of approximately several tens of microns from the surface.

In order to remove such an oxide layer, the target surface is sputtered, which is so-called pre-sputtering.

[Problem that the invention seeks to solve] However,
The above method has a problem in that the press sputtering may take several hours and the production time is long.

In addition, the portion removed by press sputtering of the target was wasted and was a cause of increased manufacturing costs.

In fact, removing 0.1 mm of the surface of a 2 mm thick target has a reduction in utilization efficiency of 5%, which cannot be ignored.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that solves the problems of the prior art described above and can produce an optical recording medium with good characteristics without increasing production time or cost.

[Means for Solving the Problems] The above object of the present invention is to take out a target material from a sealed container, prepare it in a vacuum film forming chamber, and form a thin film on a substrate using this target material as a base material. In the method for producing an optical recording medium, the container is opened in an inert gas atmosphere in a chamber connected to the vacuum film forming chamber, and the target material is placed in a vacuum acid printing chamber without being exposed to oxygen and moisture. This is achieved by transporting.

[Example] Hereinafter, the process of creating an optical recording medium based on the present invention will be explained step by step with reference to FIG.

■ In an argon-substituted atmosphere, the target material vacuum-sealed in a container is transferred to glove box 1 in an argon atmosphere.
Open it inside.

■ Transport it as it is in an argon atmosphere, perform Iwaprobil alcohol ultrasonic cleaning 3 minutes CFC cleaning in the atmosphere adjustment cleaning tank 2, and return it to the glove box 1 in an argon atmosphere.

■ Stack the backing plate, bonding agent, and target in an argon atmosphere in glove box 1.

■ Transported to atmosphere-controlled bonding furnace 3 with argon atmosphere and bonded.

■ Return it to the glove box 1 and transport it to the continuous film forming machine 4 in the glove box.

■ After creating an argon atmosphere in the film deposition preparation room, connect it to the glove box and perform the work of fixing the target in an argon atmosphere.

Here, in the production apparatus shown schematically in FIG. 1, the connecting parts of each device have the same cross section and are configured so that they can be connected in a sealed state using a rubber backing or the like.

Next, a method and results for evaluating a medium for examining the effects of the present invention will be described.

After setting the target, sputtering was performed every 30 minutes, and a laminated film having the following composition was formed on a glass substrate every 30 minutes.

Film Thickness: Amorphous silicon nitride 700 TbFeCo
800 people Amorphous silicon nitride 70
The evaluation of whether the influence of the oxidized layer on the surface of the 0-person target was eliminated was determined based on whether the laminated film had components in the in-plane direction and whether the square shape was clean.

When an experiment was conducted using the conventional method, no change was observed in the sample after 6 hours of sputtering, and the characteristics were saturated.

On the other hand, when an experiment was conducted using the method described in the present invention, the characteristics were saturated after about one hour, and a sample having the same square shape as the conventional method was obtained.

When the amount of oxygen contained inside these samples was investigated, it was found that in order for the characteristics to be saturated, the amount of internal oxygen should be reduced to 0.7%.

Incidentally, the amount of carbon present in the film was also reduced by the present invention, and it was also presumed that this resulted in an improvement in the durability performance of the film.

The present invention can be applied in various ways in addition to the embodiments described above. For example, in the embodiment, a manual method using a glove box has been described, but the same effect can be obtained by using a robot.

[Effects of the Invention] As explained above, by the method of the present invention, a clean target with a thin oxide layer could be prepared.

It has also been found that a secondary effect of reducing carbon compound contamination also occurs.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an example of a production apparatus for carrying out the method of the present invention. l...Glove box for transportation, 2...Atmosphere adjustment cleaning tank, 3...Atmosphere adjustment bonding furnace, 4...Continuous film forming machine.

Claims (1)

[Claims] (1) In a method for producing an optical recording medium in which a target material is taken out of a sealed container and prepared in a vacuum film forming chamber, and a thin film is formed on a substrate using this target material as a base material, opening the container is performed. A method for producing an optical recording medium, characterized in that the method is carried out in an inert gas atmosphere in a chamber connected to the vacuum film forming chamber, and the target material is transported to the vacuum film forming chamber without being exposed to oxygen or moisture.