CMP abrasive, liquid additive for CMP abrasive and method for polishing substrate

Abstract

A CMP abrasive comprising a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and a liquid additive containing a dispersant and water; and a liquid additive for the CMP abrasive. A method for polishing a substrate which comprises holding a substrate having, formed thereon, a film to be polished against a polishing pad of a polishing platen, followed by pressing, and moving the substrate and the polishing platen while supplying the above CMP abrasive in between the film to be polished and the polishing pad to thereby polish the film to be polished. The CMP abrasive and the method for polishing can be used for polishing a surface to be polished such as a silicone oxide film or a silicon nitride film without contaminating the surface to be polished with an alkali metal such as sodium ions and with no flaws, and the CMP abrasive is excellent in storage stability.

1 - 7 . (canceled)  
     
     
         8 . A liquid additive for CMP abrasive, comprising a dispersant and water, 
 wherein the liquid additive for CMP abrasive is to be used in a method for polishing a substrate comprising holding a substrate having, formed thereon, a film to be polished against a polishing pad of a polishing platen, followed by pressing, and moving the substrate and the polishing platen while supplying a CMP abrasive in between the film to be polished and the polishing pad to thereby polish the film to be polished; and    wherein the CMP abrasive is prepared by separately preparing, 
 a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and  
 the liquid additive for CMP abrasive containing the dispersant and water, and  
   mixing, at the time of the polishing, the cerium oxide slurry and the liquid additive for CMP abrasive.    
     
     
         9 . The liquid additive for CMP abrasive of  claim 8 , wherein the dispersant is a polymer dispersant selected from the group consisting of a polymer containing ammonium acrylate as a copolymerized ingredient, a polyammonium-acrylate and a polyamine-acrylate.  
     
     
         10 . The liquid additive for CMP abrasive of  claim 9 , wherein the polymer dispersant has a weight average molecular weight of 100 to 50,000.  
     
     
         11 . The liquid additive for CMP abrasive of  claim 9 , wherein the polymer dispersant has a molecular weight distribution (weight average molecular weight/number average molecular weight) of 1.005 to 1.300.  
     
     
         12 . The liquid additive for CMP abrasive of  claim 9 , wherein the polymer dispersant contains 10 mol % or less of free ammonia or a free amine, which does not form a salt.  
     
     
         13 . The liquid additive for CMP abrasive of  claim 8 , which contains 1 to 10% by weight of the dispersant.  
     
     
         14 . The liquid additive for CMP abrasive of  claim 13 , wherein the dispersant is a polyammonium-acrylate or a polyamine-acrylate.  
     
     
         15 . The liquid additive for CMP abrasive of  claim 14 , wherein each of the polyammonium-acrylate and the polyamine-acrylate has a weight average molecular weight of 1,000 to 100,000.  
     
     
         16 . The liquid additive for CMP abrasive of  claim 15 , wherein each of the polyammonium-acrylate and the polyamine-acrylate has a molecular weight distribution (weight average molecular weight/number average molecular weight) of 1.005 to 1.300.  
     
     
         17 . The liquid additive for CMP abrasive of  claim 14 , wherein each of the polyammonium-acrylate and the polyamine-acrylate contains 10 mol % or less of free ammonia or a free amine, which does not form a salt.  
     
     
         18 . The liquid additive for CMP abrasive of  claim 8 , which is pH 4 to 8.  
     
     
         19 . The liquid additive for CMP abrasive of  claim 8 , which has a viscosity of 1.20 to 2.50 mPa·s.