| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass substrate or a magnetic recording medium capable of manufacturing with high productivity a glass substrate for a magnetic recording medium having a highly smooth surface and less wavy surface. <P>SOLUTION: Primary, secondary and tertiary lapping processes use diamond pads 20A, 20B, 20C, respectively. In the diamond pad 20A, the average grain diameter of diamond abrasive grains is 4 to 12 μm, and the content of the diamond abrasive grains is 5 to 70 volume%. In the diamond pad 20B, the average grain diameter of diamond abrasive grains is 1 to 5 μm, and the content of the diamond abrasive grains is 5 to 80 volume%. In the diamond pad 20C, the average grain diameter of diamond abrasive grains is equal to and more than 0.2 μm and less than 2 μm, and the content of the diamond abrasive grains is 5 to 80 volume%. In a primary polishing process, cerium oxide is not used but silicon oxide is used as an abrasive, and a step for performing an etching process is provided before a step for performing the polishing process. <P>COPYRIGHT: (C)2012,JPO&INPIT |
