| 摘要 |
PROBLEM TO BE SOLVED: To provide a disk having less micro flaws and having high surface flatness by performing the displacement of a substrate between producing steps while holding non-recording regions of the substrate. SOLUTION: Al-base metallic substrate is produced by passing a blank material which is formed by cutting a belt-like sheet into a shape of the disk substrate through a chamfering step for grinding the cutting corner part, a grinding step for the smooth grinding, a step for non-magnetically treating the base such as a plating, a polishing step for specularly finishing the surface thereof, a texturing step and, thereafter as necessary, a step for forming the non- magnetic base layer. In particular, it is indispensable to perform the displacement of the substrate between the respective steps on and after the polishing step while holding the non-recording regions of the substrate. As for the method for holding the non-recording region of the substrate, a method for gripping an inner periphery or an outer periphery of a doughnut-type substrate, desirably the non-recording region of the inner periphery or the outer periphery, or a method for restraining the same with an inner periphery wall or outer periphery wall or the like are exemplified.
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