Semiconductor polishing compound, process for its production and polishing method

Abstract

A semiconductor polishing compound comprising cerium oxide abrasive grains, water and an additive, wherein the additive is a water-soluble organic polymer such as ammonium polyacrylate or an anionic surfactant, the pH at 25° C. is from 3.5 to 6, and the concentration of the additive is from 0.01 to 0.5% based on the total mass of the polishing compound. This polishing compound simultaneously has dispersion stability, excellent scratch characteristics and excellent polishing planarization characteristics. In particular, this polishing compound provides excellent planarization characteristics having dishing fluctuation reduced, when used for polishing a semiconductor substrate having a silicon nitride film 3 and a silicon oxide film 2 formed on a silicon substrate 1 . Further, the time for polishing a pattern wafer can be shortened by using this polishing compound.

1 . A semiconductor polishing compound comprising cerium oxide abrasive grains, water and an additive, wherein the additive is at least one member selected from the group consisting of a water-soluble organic polymer and an anionic surfactant, the pH of the polishing compound at 25° C. is from 3.5 to 6, and the total concentration of the additive is from 0.01 to 0.5% based on the total mass of the polishing compound.  
     
     
         2 . The semiconductor polishing compound according to  claim 1 , wherein the additive is a water-soluble organic polymer having carboxylic acid groups or carboxylate groups.  
     
     
         3 . The semiconductor polishing compound according to  claim 2 , wherein the water-soluble organic polymer is polyacrylic acid or ammonium polyacrylate.  
     
     
         4 . The semiconductor polishing compound according to  claim 2 , wherein the water-soluble organic polymer has a molecular weight of from 1,000 to 500,000.  
     
     
         5 . The semiconductor polishing compound according to  claim 1 , which further contains an inorganic acid or an inorganic salt.  
     
     
         6 . A process for producing a semiconductor polishing compound, which comprises mixing liquid A comprising cerium oxide abrasive grains and water, and liquid B comprising an additive which is at least one member selected from the group consisting of a water-soluble organic polymer and an anionic surfactant, and water, so that the pH of the polishing compound at 25° C. is from 3.5 to 6, and the total concentration of the additive is from 0.01 to 0.5% based on the total mass of the polishing compound.  
     
     
         7 . The process for producing a semiconductor polishing compound according to  claim 6 , wherein the additive is a water-soluble organic polymer having carboxylic acid groups or carboxylate groups.  
     
     
         8 . The process for producing a semiconductor polishing compound according to  claim 7 , wherein the water-soluble organic polymer is polyacrylic acid or ammonium polyacrylate.  
     
     
         9 . The process for producing a semiconductor polishing compound according to  claim 6 , wherein liquid B contains an inorganic acid or an inorganic salt.  
     
     
         10 . A polishing method which comprises bringing a surface to be polished and a polishing pad in contact with each other and relatively moving them, while supplying a semiconductor polishing compound, characterized in that the polishing compound is a semiconductor polishing compound comprising cerium oxide abrasive grains, water and an additive, wherein the additive is at least one member selected from the group consisting of a water-soluble organic polymer and an anionic surfactant, the pH of the polishing compound at 25° C. is from 3.5 to 6, and the total concentration of the additive is from 0.01 to 0.5% based on the total mass of the polishing compound, and the surface to be polished is a semiconductor substrate.  
     
     
         11 . The polishing method according to  claim 10 , wherein the semiconductor substrate is a substrate for a semiconductor device, which comprises at least a silicon oxide film  2 .  
     
     
         12 . The polishing method according to  claim 10 , wherein the semiconductor substrate is one having a silicon nitride film  3  and a silicon oxide film  2  formed on a silicon substrate  1 .  
     
     
         13 . The polishing method according to  claim 10 , wherein the additive is a water-soluble organic polymer having carboxylic acid groups or carboxylate groups.  
     
     
         14 . The polishing method according to  claim 10 , wherein the water-soluble organic polymer is polyacrylic acid or ammonium polyacrylate.  
     
     
         15 . The polishing method according to  claim 10 , wherein the polishing compound further contains an inorganic acid or an inorganic salt.