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 . A cerium oxide slurry, comprising cerium oxide particles, a dispersant and water, 
 wherein the cerium oxide slurry 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, the cerium oxide slurry containing the cerium oxide particles, the dispersant and water, and  
 a liquid additive for CMP abrasive containing a dispersant and water, and  
 mixing, at the time of the polishing, the cerium oxide slurry and the liquid additive for CMP abrasive.  
   
   
   
       2 . The cerium oxide slurry of  claim 1 , 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.  
   
   
       3 . The cerium oxide slurry of  claim 2 , wherein the polymer dispersant has a weight average molecular weight of 100 to 50,000.  
   
   
       4 . The cerium oxide slurry of  claim 2 , wherein the polymer dispersant has a molecular weight distribution (weight average molecular weight/number average molecular weight) of 1.005 to 1.300.  
   
   
       5 . The cerium oxide slurry of  claim 2 , wherein the polymer dispersant contains 10 mol % or less of free ammonia or a free amine, which does not form a salt.  
   
   
       6 . The cerium oxide slurry of  claim 1 , which contains 0.01 to 2.0 parts by weight of the dispersant relative to 100 parts by weight of the cerium oxide particles and contains 0.3 to 40% by weight of the cerium oxide particles based on the cerium oxide slurry.  
   
   
       7 . The cerium oxide slurry of  claim 1 , which is pH 6 to 10.