US 12,440,939 B2
Polishing agent for synthetic quartz glass substrate, method for manufacturing the polishing agent, and method for polishing synthetic quartz glass substrate
Mitsuhito Takahashi, Annaka (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Appl. No. 17/045,189
Filed by SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
PCT Filed Feb. 20, 2019, PCT No. PCT/JP2019/006198
§ 371(c)(1), (2) Date Oct. 5, 2020,
PCT Pub. No. WO2019/207926, PCT Pub. Date Oct. 31, 2019.
Claims priority of application No. 2018-083099 (JP), filed on Apr. 24, 2018.
Prior Publication US 2021/0162558 A1, Jun. 3, 2021
Int. Cl. B24B 7/24 (2006.01); C09K 3/14 (2006.01)
CPC B24B 7/241 (2013.01) [C09K 3/1409 (2013.01)] 13 Claims
 
1. A polishing agent for a synthetic quartz glass substrate, comprising polishing particles and water, wherein
the polishing particles comprise composite oxide particles of cerium and yttrium,
a content by percent of the cerium in the polishing particles is 71 mol % or more and 79 mol % or less,
a content by percent of the yttrium in the polishing particles is 21 mol % or more and 29 mol % or less,
the polishing particles have an average primary particle size of 100 nm to 500 nm,
the polishing particles are wet ceria particles and
the polishing agent has a pH within a range of 3.0 or more and 8.0 or less.