Cmp Polishing Slurry and Method of Polishing Substrate

Abstract

A CMP polishing slurry of the present invention contains cerium oxide particles, water, and a polymer of at least one of a methacrylic acid and the salt thereof, and/or a polymer of at least one of a methacrylic acid and the salt thereof and a monomer having an unsaturated double bond, preferably contains furthermore a dispersant or a polymer of monomers containing at least one of an acrylic acid and the salt thereof. The present invention provides a CMP polishing slurry and a polishing method that, after polishing, give a polished film having a smaller difference in residual film thickness due to a pattern density difference.

1 . A CMP polishing slurry, containing (A) cerium oxide particles, (B) a dispersant, (C) water, and (D) at least one of a polymer of at least one of a methacrylic acid and the salt thereof, and a polymer of at least one of a methacrylic acid and the salt thereof and a monomer having an unsaturated double bond. 
   
   
       2 . A CMP polishing slurry, containing (A) cerium oxide particles, (C) water, and (D) at least one of a polymer of at least one of a methacrylic acid and the salt thereof, and a polymer of at least one of a methacrylic acid and the salt thereof and a monomer having an unsaturated double bond. 
   
   
       3 . A CMP polishing slurry, containing (A) cerium oxide particles, (C) water, (D) at least one of a polymer of at least one of a methacrylic acid and the salt thereof, and a polymer of at least one of a methacrylic acid and the salt thereof and a monomer having an unsaturated double bond, and (E) at least one of a polymer of at least one of an acrylic acid and the salt thereof and a polymer of at least one of an acrylic acid and the salt thereof and a monomer having an unsaturated double bond. 
   
   
       4 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the content of the methacrylic acid and the salt thereof for the polymer (D) is 10 to 100 mol % with respect to the total amount of the monomer components. 
   
   
       5 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein a polymerization initiator for use in preparation of the polymer is a compound soluble completely at 25° C. when it is added at a ratio of 0.5 part in 99.5 mass parts of water or a compound soluble at 25° C. when it is added at a ratio of 0.5 mass part in 99.5 mass parts of water and at least one of an organic acid and an inorganic acid is added thereto in an amount of 2 moles with respect to 1 mole of the polymerization initiator. 
   
   
       6 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein a polymerization initiator for use in preparation of the polymer is a compound soluble completely at 25° C. when it is added at a ratio of 3.0 parts in 97.0 mass parts of water or a compound soluble at 25° C. when it is added at a ratio of 3.0 mass parts in 97.0 mass parts of water and at least one of an organic acid and an inorganic acid is added thereto in an amount of 2 moles with respect to 1 mole of the polymerization initiator. 
   
   
       7 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the amount of the polymer added is 0.01 to 5 mass parts with respect to 100 mass parts of the CMP polishing slurry. 
   
   
       8 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the weight-average molecular weight of the polymer is 200 to 100,000. 
   
   
       9 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the average particle diameter of the cerium oxide particles is 1 to 400 nm. 
   
   
       10 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the amount of the cerium oxide particles added is 0.1 to 5 mass parts with respect to 100 mass parts of the CMP polishing slurry. 
   
   
       11 . The CMP polishing slurry according to any one of  claims 1  to  3 , wherein the pH of the polishing slurry is 4.5 to 6.0. 
   
   
       12 . The CMP polishing slurry according to any one of  claims 1  to  3 , further containing a strong acid ion, wherein the content of the strong acid ion is 50 to 10,000 ppm by mass with respect to the CMP polishing slurry. 
   
   
       13 . A method of polishing a substrate, characterized by pressing a substrate having a formed film to be polished onto a polishing cloth of a polishing table, and polishing the film to be polished by moving the substrate and the polishing table relatively to each other while supplying the CMP polishing slurry according to any one of  claims 1  to  3  into the space between the film to be polished and the polishing cloth.