Polishing composition, polishing method, and method for manufacturing substrate

Abstract

Provided are a polishing composition, a polishing method, and a method for manufacturing a substrate. The polishing composition contains polishing abrasive grains, an additive molecule, a pH adjusting agent, and a dispersing medium. The polishing abrasive grains contain silica particles, and the silanol group density on the surface of the silica particles is 0 to 3.0 groups/nm 2 . The silanol group density is calculated and determined based on the specific surface area measured by the BET method and the amount of silanol groups measured by titration. The pH adjusting agent is used to adjust the pH of the polishing composition to a range of 1.5 or more and 4.5 or less. The additive molecule has a structure represented by Formula (I). (In Formula (I), R 1 , R 2 , n, m, p, q, and r are as defined in the specification.)

What is claimed is: 
     
         1 . A polishing composition comprising:
 polishing abrasive grains containing silica particles, a silanol group density on a surface of the silica particles being 0 to 3.0 groups/nm 2 ,   the silanol group density being calculated and determined based on a specific surface area measured by a BET method and an amount of silanol groups measured by titration;   an additive molecule having a structure represented by Formula (I):   
       
         
           
           
               
               
           
         
         wherein in Formula (I), 
         R 1  and R 2  are each independently H, a C 1  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 18  linear alkenyl group; 
         n is an integer 2 to 40; and 
         m, p, and q are each independently 0 or 1, r is an integer 0 to 2, R 1  is a C 1  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 18  linear alkenyl group when m is 1, and R 2  is a C 1  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 18  linear alkenyl group when p is 1; 
         a pH adjusting agent used to adjust a pH of the polishing composition to a range of 1.5 or more and 4.5 or less; and 
         a dispersing medium. 
       
     
     
         2 . The polishing composition according to  claim 1 , wherein a content of the additive molecule is 50 to 10,000 ppm by weight with respect to a total weight of the polishing composition. 
     
     
         3 . The polishing composition according to  claim 1 , wherein a weight average molecular weight of the additive molecule is 100 to 10000. 
     
     
         4 . The polishing composition according to  claim 1 , wherein
 in Formula (I),   R 1  is H and R 2  is a C 1  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 18  linear alkenyl group;   n is an integer 2 to 20; and   m, p, q, and r are all 0.   
     
     
         5 . The polishing composition according to  claim 1 , wherein
 in Formula (I),   R 1  and R 2  are both H;   n is an integer 2 to 40; and   m and p are both 0 and q and r are both 1.   
     
     
         6 . The polishing composition according to  claim 1 , wherein
 in Formula (I),   R 1  is a C 1  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 28  linear alkenyl group and R 2  is H;   n is an integer 2 to 20; and   m and p are both 0 and q and r are both 1.   
     
     
         7 . The polishing composition according to  claim 1 , wherein
 in Formula (I),   R 1  is a C 2  to C 18  linear alkyl group, a C 3  to C 18  branched alkyl group, or a C 2  to C 28  linear alkenyl group and R 2  is H;   n is an integer 2 to 20; and   m, q, and r are all 1 and p is 0.   
     
     
         8 . The polishing composition according to  claim 1 , wherein
 in Formula (I),   R 1  and R 2  are both H;   n is an integer 2 to 20; and   m, p, and q are all 0 and r is 2.   
     
     
         9 . The polishing composition according to  claim 1 , wherein a content of the polishing abrasive grains is 0.1% to 10% by weight with respect to a total weight of the polishing composition. 
     
     
         10 . A polishing method comprising:
 polishing an object to be polished using the polishing composition according to any one of  claims 1  to  9 , wherein a material for the object to be polished includes an oxide and a silicon-containing material, and the silicon-containing material is represented by Si x Ge 1-x  where x=0.1 to 1.   
     
     
         11 . The polishing method according to  claim 10 , wherein a removal rate of the polishing composition with respect to the oxide is a first removal rate R1 and a removal rate of the polishing composition with respect to the silicon-containing material is a second removal rate R2 when a polishing pressure is 1.0 psi, and a ratio value R1/R2 of the first removal rate to the second removal rate is 10 or more. 
     
     
         12 . A method for manufacturing a substrate, the method comprising:
 preparing a substrate, a surface of the substrate containing an oxide and a silicon-containing material, the silicon-containing material being represented by Si x Ge 1-x  where x=0.1 to 1; and   polishing the substrate using the polishing composition according to any one of  claims 1  to  9 .