The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 14, 2024
Filed:
Jan. 27, 2023
Nissan Chemical Corporation, Tokyo, JP;
NISSAN CHEMICAL CORPORATION, Tokyo, JP;
Abstract
Provided is a method that is for polishing a silicon wafer by a polishing device using a carrier holding the silicon wafer, and that can reduce wear on the carrier. In this polishing method, a polishing liquid used in the polishing device contains 0.1-5 mass %, in terms of the concentration of silica, silica particles comprising: silica particles (A) having an average primary particle size of 4-30 nm as measured by BET, and having an (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET; and silica particles (B) having an average primary particle size of more than 30 nm but not more than 50 nm as measured by BET, and having a (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET, wherein the mass ratio of the silica particles (A) to the silica particles (B) is 100:0 to 85:15.