Polishing agent and polishing method

Abstract

The present invention relates to a polishing agent for polishing a surface to be polished of an object to be polished, the polishing agent including: first silicon oxide fine particles having an average primary particle size of 5 to 20 nm; second silicon oxide fine particles having an average primary particle size of 40 to 110 nm; and water, in which a ratio of the first silicon oxide fine particles to a total amount of the first silicon oxide fine particles and the second silicon oxide fine particles is from 0.7 to 30% by mass.

1 . A polishing agent for polishing a surface to be polished of an object to be polished, the polishing agent comprising:
 first silicon oxide fine particles having an average primary particle size of 5 to 20 nm;   second silicon oxide fine particles having an average primary particle size of 40 to 110 nm; and   water,   wherein a ratio of the first silicon oxide fine particles to a total amount of the first silicon oxide fine particles and the second silicon oxide fine particles is from 0.7 to 30% by mass.   
     
     
         2 . The polishing agent according to  claim 1 , wherein both the first silicon oxide fine particles and the second silicon oxide fine particles are colloidal silica. 
     
     
         3 . The polishing agent according to  claim 1 , wherein the ratio of the first silicon oxide fine particles to the total amount of the first silicon oxide fine particles and the second silicon oxide fine particles is from 1 to 10% by mass. 
     
     
         4 . The polishing agent according to  claim 1 , wherein the second silicon oxide fine particles have an average primary particle size of 45 to 100 nm. 
     
     
         5 . The polishing agent according to  claim 1 , wherein the first silicon oxide fine particles have an average primary particle size of 5 to 15 nm. 
     
     
         6 . The polishing agent according to  claim 1 , wherein the object to be polished is a single-crystal substrate having a revised Mohs hardness of 10 or more. 
     
     
         7 . A polishing method comprising:
 supplying the polishing agent according to  claim 1  to a polishing pad; and   bringing the polishing pad into contact with a surface to be polished of an object to be polished to perform polishing by relative movement between the polishing pad and the surface to be polished.   
     
     
         8 . The polishing method according to  claim 7 , wherein an operation of recovering the polishing agent supplied to the polishing pad and used for polishing, and of supplying again the recovered polishing agent to the polishing pad is repeated, thereby using the polishing agent in cycles.