Asahi Glass Company, Limited

Kazuo Mannami

Osamu Miyahara

Mizuho Ishida

Katsuhiro Matsumoto

Tsutomu Maruyama

Norihito Shida

Kuniyuki Someya

The present invention relates to a method for producing a glass substrate for a magnetic disk, the method including a step of polishing a main surface of a circular glass plate while supplying a polishing slurry containing a polishing material, in which polishing is performed, after a polishing surface is subjected to dressing treatment, by using a polishing pad having: a first resin foam layer which forms the polishing surface, includes a resin foam having pores with a pore diameter of more than 20 &#x3bc;m and has a thickness of 400 &#x3bc;m or less; and a second resin foam layer which is provided between a platen for fixing the polishing pad and the first resin foam layer, includes a resin foam having pores with a pore diameter of 20 &#x3bc;m or less and has a thickness of 50 to 250 &#x3bc;m, and in which a total thickness of the first resin foam layer and the second resin foam layer is 550 &#x3bc;m or less, and a international rubber hardness degree of the polishing pad measured by the M method according to JIS K6253 is 40 IRHD or more.

Glass substrate for magnetic disk and method for producing the same

A method for cleaning a disk-shape glass substrate, which comprises rotating the disk-shape glass substrate on its center with its main surface vertical, and making a cleaning fluid irradiated with ultrasonic waves run down on the outer peripheral edge surface of the rotating glass substrate.

Method for cleaning disk-shape glass substrate and magnetic disk

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Ayutthaya, Thailand

Kazuo Mannami