Abrasive slurry having high dispersion stability and manufacturing method for a substrate

Abstract

To provide an abrasive slurry having high dispersion stability, including: abrasive fine particles made of one or more kinds of oxides; colloidal fine particles made of colloidal oxide with an average particle size smaller than an average particle size of the abrasive fine particles; and a dispersion medium in which the abrasive fine particles and the colloidal fine particles are dispersed, and a manufacturing method for a substrate as an inorganic substrate, including polishing the substrate using the abrasive slurry. An abrasive slurry according to the present invention keeps high dispersion stability for a long time and shows a satisfactory redispersion property, which can eliminate a problem about precipitation/aggregation as much as possible and can be used as a dispersant-free abrasive containing absolutely no organic dispersant. In particular, by using the abrasive slurry, it is possible to manufacture a substrate such as a silicon substrate used in a semiconductor manufacturing process or an aluminum substrate used in an electrostatic chuck manufacturing process through CMP with industrial advantage.

1 . An abrasive slurry having high dispersion stability, consisting of: 
 abrasive fine particles made of one or more kinds of oxides;    colloidal fine particles made of colloidal oxide with an average particle size smaller than an average particle size of the abrasive fine particles; and    a dispersion medium in which the abrasive fine particles and the colloidal fine particles are dispersed;    wherein the average particle size (Dp) of the abrasive fine particles is 100 to 5,000 nm, the average particle size (Dc) of the colloidal fine particles is 10 to 300 nm, and a particle size ratio (Dc/Dp) of the average particle size (Dc) of the colloidal fine particles to the average particle size (Dp) of the abrasive fine particles is 10 or less, and the abrasive fine particles have a particle concentration (Cp) of 5 to 30 wt %, the colloidal fine particles have a particle concentration (Cc) of 0.01 to 7.5 wt %, and a weight distribution ratio (Cc/Cp) of the particle concentration (Cc) of the colloidal fine particles to the particle concentration (Cp) of the abrasive fine particles is 0.002 to 1.5.    
   
   
       2 . The abrasive slurry having high dispersion stability according to  claim 1 , wherein the dispersion medium comprises water or an aqueous dispersion medium mainly containing water.  
   
   
       3 . The abrasive slurry having high dispersion stability according to  claim 1 , wherein the abrasive fine particles comprise a cerium oxide particle.  
   
   
       4 . The abrasive slurry having high dispersion stability according to  claim 1 , wherein the colloidal fine particles comprise a colloidal silica.  
   
   
       5 . The abrasive slurry having high dispersion stability according to any one of  claim 1 , wherein the colloidal fine particles have the particle concentration (Cc) of 0.015 to 6.25 wt %, and a weight distribution ratio (Cc/Cp) of the particle concentration (Cc) of the colloidal fine particles to the particle concentration (Cp) of the abrasive fine particles is 0.003 to 1.25.  
   
   
       6 . The abrasive slurry having high dispersion stability according to any one of  claims 1  to  5 , wherein no organic dispersant is contained therein.  
   
   
       7 . A manufacturing method for a substrate as an inorganic substrate, comprising polishing the substrate using the abrasive slurry according to any one of  claim 1 .  
   
   
       8 . The manufacturing method for a substrate according to  claim 7 , wherein the substrate has a surface on which an oxide film is formed.  
   
   
       9 . A manufacturing method for a substrate as an inorganic substrate, comprising polishing the substrate using the abrasive slurry according to  claim 6.