US 12,173,193 B2
Polishing agent for synthetic quartz glass substrate and method for polishing synthetic quartz glass substrate
Mitsuhito Takahashi, Annaka (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Appl. No. 16/765,040
Filed by SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
PCT Filed Oct. 18, 2018, PCT No. PCT/JP2018/038758
§ 371(c)(1), (2) Date May 18, 2020,
PCT Pub. No. WO2019/097945, PCT Pub. Date May 23, 2019.
Claims priority of application No. 2017-222254 (JP), filed on Nov. 17, 2017.
Prior Publication US 2020/0399504 A1, Dec. 24, 2020
Int. Cl. C09G 1/02 (2006.01); B24B 37/04 (2012.01); C03C 19/00 (2006.01); C09K 3/14 (2006.01)
CPC C09G 1/02 (2013.01) [B24B 37/044 (2013.01); C03C 19/00 (2013.01); C09K 3/1409 (2013.01); C09K 3/1454 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A polishing agent for a synthetic quartz glass substrate, the polishing agent comprising:
wet ceria particles; and
non-spherical silica particles, wherein
the wet ceria particles have an average primary particle diameter of 30 nm to 50 nm,
the non-spherical silica particles have an average primary particle diameter of 80 nm to 120 nm,
the wet ceria particles have a degree of association of 1.0 to 3.0,
the non-spherical silica particles are associated silica particles and have a degree of association of 2.0 to 3.5,
a content of the wet ceria particles in the polishing agent is 1.5 times to 3.0 times as high as a content of the non-spherical silica particles in a mass ratio, and
a total content of the wet ceria particles and the non-spherical silica particles in the polishing agent is more than 20 parts by mass to 50 parts by mass per 100 parts by mass of the polishing agent.