Polishing composition and polishing method

Abstract

A polishing composition includes colloidal silica. The colloidal silica has such a particle diameter as to satisfy the relationship of the inequality: D SA ≦D N4 , between an average primary particle diameter D SA of the colloidal silica calculated on the basis of a BET method and an average secondary particle diameter D N4 of the colloidal silica measured by a laser diffraction method. The colloidal silica has the average secondary particle diameter D N4 of 30 nm or smaller. The polishing composition can inhibit a polishing rate from remarkably decreasing due to clogging in a polishing pad.

1 . A polishing composition used for polishing an object with the use of a polishing pad, the polishing composition comprising colloidal silica, wherein the colloidal silica has such a particle diameter as to satisfy the relationship of the inequality: D SA ≦D N4 , between an average primary particle diameter D SA  of the colloidal silica calculated on the basis of a BET method and an average secondary particle diameter D N4  of the colloidal silica measured by a laser diffraction method, and has the average secondary particle diameter D N4  of 30 nm or smaller.  
     
     
         2 . The polishing composition according to  claim 1 , wherein the colloidal silica has the average secondary particle diameter D N4  of 20 nm or smaller.  
     
     
         3 . The polishing composition according to  claim 1 , wherein the colloidal silica has the average secondary particle diameter D N4  of 5 nm or larger.  
     
     
         4 . The polishing composition according to  claim 1 , wherein the colloidal silica has the average primary particle diameter D SA  of 20 nm or smaller.  
     
     
         5 . The polishing composition according to  claim 4 , wherein the colloidal silica has the average primary particle diameter D SA  of 10 nm or smaller.  
     
     
         6 . The polishing composition according to  claim 1 , wherein the colloidal silica has the average primary particle diameter D SA  of 3 nm or larger.  
     
     
         7 . The polishing composition according to  claim 1 , wherein the colloidal silica has such a relationship as to satisfy the inequality: D N4 ≦3×D SA , between the average primary particle diameter D SA  and the average secondary particle diameter D N4 .  
     
     
         8 . The polishing composition according to  claim 1 , further comprising an alkaline compound.  
     
     
         9 . The polishing composition according to  claim 1 , further comprising a chelating agent.  
     
     
         10 . The polishing composition according to  claim 1 , further comprising an anionic surface active agent.  
     
     
         11 . A polishing method comprising: 
 preparing a polishing composition including colloidal silica which has the particle diameter of satisfying the relationship of the inequality: D SA ≦D N4 , between an average primary particle diameter D SA  of the colloidal silica calculated on the basis of a BET method and an average secondary particle diameter D N4  of the colloidal silica measured by a laser diffraction method, and has the average secondary particle diameter D N4  of 30 nm or smaller; and    polishing an object with the use of a polishing pad, by using the prepared polishing composition.