| 简介 |
PROBLEM TO BE SOLVED : To provide a manufacturing method of a glass substrate for a magnetic disk by which etching by washing does not give influence on the smoothness of a final glass substrate principal surface after a second polishing (mirror-surface polishing) step while an abrasive used in a first polishing (coarsely polishing) step and consisting essentially of a rare earth oxide is effectively removed by washing. SOLUTION : In a washing step for washing the glass substrate performed between the coarsely polishing step and the mirror-surface polishing step, the glass substrate is brought into contact with a washing liquid containing ascorbic acid, 100 to 1, 000 ppm fluorine ion and ≥3 wt.% sulfuric acid. Thereby, even when surface roughness increases by etching accompanying washing, the increase of the surface roughness generates in the range of machining allowance in the mirror-surface polishing step performed later. COPYRIGHT : (C)2009, JPO&INPIT |
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