DISK SUBSTRATE FOR VERTICAL MAGNETIC RECORDING MEDIUM, VERTICAL MAGNETIC RECORDING MEDIUM USING SUBSTRATE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To prevent reduction of fracture strength of a glass substrate even when the glass substrate whose soft magnetic under layer is plated is subjected to annealing treatment. SOLUTION: The reduction of fracture strength in the directions parallel and vertical to the surface of the glass substrate 1 is prevented even in the glass substrate 1 whose soft magnetic under layer 5 is plated and subjected to annealing treatment since an end surface of the glass substrate 1 is worked into a round face based on a prescribed round face working condition. COPYRIGHT: (C)2006,JPO&NCIPI