Method for cleaning main carrier

Abstract

To provide a cleaning method of master carrier which removes depositions to a master carrier without re-attachment by means of a dry process and non-contact and allows magnetic transfer of high transfer quality. The master carrier 2 for magnetic transfer or optical disk before performing magnetic transfer or optical disk molding is stored in a vacuum vessel 3, the inside of the vessel 3 is evacuated by a pressure reducing means 4, plasma discharge is generated between an electrode 52 and the master carrier 2 by a discharging means 5 in the state that a reactive gas is introduced into the vessel 3 by a gas introducing means 6 and the depositions on the surface of the master carrier 2 is removed by combustion by utilizing plasma etching.

Description

technical field [0001] The present invention relates to a method for cleaning a master carrier for magnetic transcription used in magnetic transcription or a master carrier for optical discs used in optical disc molding. Background technique [0002] The magnetic transcription method is to apply a magnetic field for transcription under the state that the information bearing surface of the master carrier carrying the transcription information through the fine concave-convex pattern of the magnetic body is in close contact with the slave medium having the magnetic recording part that accepts the transcription, and the magnetic field will be applied to the master carrier. A method of transcribing and recording the magnetization pattern corresponding to the transcribed information (such as a servo signal) carried on the slave medium. Such a magnetic transcription method is disclosed in, for example, JP-A-63-183623, JP-A-10-40544, JP-A-10-269566, and the like. [0003] The maste...

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Problems solved by technology

[0014] Moreover, since the optical disc is not cleaned in the middle of molding, and the optical disc is continuously formed, if the number of molding sheets exceeds 1000, as with the magnetic transcription master carrier, the resulting optical disc will be damaged due to the adhesion of foreign matter. The error rate tends to increase, making it difficult to produce highly reliable discs

[0015] According to the above, the partial cleaning of the main carrier for optical discs can use electrolytic degreasing, ultrasonic cleaning with cleaning agents, or ozone cleaning devices, etc., but sometimes the firmly attached deposits cannot be removed.

In particular, it is difficult to completely remove foreign matter in the concavity of the concavo-convex portion of the signal pattern, which causes molding failure.

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