| 摘要 |
PURPOSE:To obtain a substrate enabling the correct readout of information and having superior strength by using Al as a base material for an optical disk, forming a thin Al film on the surface and providing fine unevenness for signal information or a tracking guide to the surface to the Al film. CONSTITUTION:At least one side of Al as a base material is mirror-polished and coated with a thin Al film, and a resist applying stage, an etching pattern forming stage and a dry etching stage are successively carried out. Thus, fine unevenness for signal information or a tracking guide is provided to the surface of the Al film and an Al substrate for an optical disk is obtd. By this method, a lightweight substrate having such high strength that the substrate can withstand high-speed rotation and undergoing no change with the lapse of time, is obtd.
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