| 摘要 |
PURPOSE:To improve a manufacturing yield in a mastering step by providing such a structure that a master glass disk used in a step mastering optical media has an unpenetrated center hole. CONSTITUTION:In terms of the optical media manufacturing master glass disk 1 having a center hold 2 with a depth half the thickness of the glass 1, its surface 3 is resist-coated on a rotating stage, and is machined such as laser beam cutting and resist-development. If the center hole 2 is penetrated, a treatment solution entering a clearance between the hole and the central axis of the rotating stage flows out and soils a master disk afterwards. However such a phenomenon never occurs, whereby the yield in the mastering step can be improved.
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