Method for manufacturing glass substrate, method for manufacturing magnetic disk, and polishing liquid composition for glass substrate

Patent metadata

Field	Value
Publication number	US-2016118073-A1
Application number	US-201414894900-A
Country	US
Kind code	A1
Filing date	Jun 29, 2014
Priority date	Jun 29, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

The present invention provides a method for manufacturing a glass substrate for a magnetic disk or the like according to which surface roughnesses of main surfaces of a glass substrate can be reduced more than with currently available methods. In the present invention, by mirror-polishing (final finishing-polishing) the main surfaces of the glass substrate used in a magnetic disk, for example, using a polishing liquid containing organic-based particles made of a styrene-based resin, an acrylic resin, or a urethane-based resin, as polishing abrasive particles, surface roughnesses of the main surfaces of the substrate can be reduced more than with currently available methods.

First claim

1 . A method for manufacturing a glass substrate, comprising:
mirror-polishing main surfaces of the glass substrate using a polishing liquid containing organic-based particles as polishing abrasive particles.

2 . The method for manufacturing the glass substrate according to claim 1 , wherein
the organic-based particles are made of a styrene-based resin, an acryl-based resin, or a urethane-based resin.

3 . The method for manufacturing the glass substrate according to claim 1 , wherein
a particle diameter of the organic-based particles is in a range of 0.5 to 60 μm.

4 . The method for manufacturing the glass substrate according to claim 1 , wherein
after the main surfaces of the glass substrate are polished using a polishing liquid containing silica abrasive particles as polishing abrasive particles, the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles.

5 . The method for manufacturing the glass substrate according to claim 1 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

6 . The method for manufacturing the glass substrate according to claim 1 , wherein
after the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, the glass substrate is cleaned using an alcohol-based cleaning agent.

7 . The method for manufacturing the glass substrate according to claim 1 , wherein
the glass substrate is a magnetic-disk glass substrate.

8 . The method for manufacturing a glass substrate according to claim 1 , wherein
the glass substrate is a glass substrate for a mask blank.

9 . A method for manufacturing a magnetic disk, in which
at least a magnetic layer is formed on a magnetic-disk glass substrate that is obtained with the manufacturing method according to claim 7 .

10 . A polishing liquid composition for a glass substrate, which is to be applied in polishing processing for polishing surfaces of a glass substrate, the polishing liquid composition comprising:
organic-based particles as polishing abrasive particles.

11 . The polishing liquid composition for the glass substrate according to claim 10 , wherein
a particle diameter of the organic-based particles is in a range of 0.5 to 60 μm.

12 . The method for manufacturing the glass substrate according to claim 2 , wherein
a particle diameter of the organic-based particles is in a range of 0.5 to 60 μm.

13 . The method for manufacturing the glass substrate according to claim 2 , wherein
after the main surfaces of the glass substrate are polished using a polishing liquid containing silica abrasive particles as polishing abrasive particles, the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles.

14 . The method for manufacturing the glass substrate according to claim 3 , wherein
after the main surfaces of the glass substrate are polished using a polishing liquid containing silica abrasive particles as polishing abrasive particles, the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles.

15 . The method for manufacturing the glass substrate according to claim 12 , wherein
after the main surfaces of the glass substrate are polished using a polishing liquid containing silica abrasive particles as polishing abrasive particles, the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles.

16 . The method for manufacturing the glass substrate according to claim 2 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

17 . The method for manufacturing the glass substrate according to claim 3 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

18 . The method for manufacturing the glass substrate according to claim 4 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

19 . The method for manufacturing the glass substrate according to claim 12 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

20 . The method for manufacturing the glass substrate according to claim 13 , wherein
with regard to roughnesses of the main surfaces of the glass substrate before the main surfaces of the glass substrate are mirror-polished using the polishing liquid containing the organic-based particles as polishing abrasive particles, an arithmetic mean roughness Ra is 0.3 nm or less.

Assignees

• Hoya Corp

Inventors

• Tawara Yoshihiro

Classifications

• G11B5/62

  Record carriers characterised by the selection of the material · CPC title

• B24B37/08

  for double side lapping · CPC title

• C09K3/1409

  Abrasive particles per se (preparation of diamond C01B32/25) · CPC title

• G11B5/8404 Primary

  manufacturing base layers · CPC title

• C09K3/1454

  Abrasive powders, suspensions and pastes for polishing · CPC title