Polishing composition

Abstract

A polishing composition comprising an abrasive having an average primary particle size of 200 nm or less, an oxidizing agent, an acid having a pK1 of 2 or less and/or a salt thereof, and water, wherein the acid value (Y) of the polishing composition is 20 mg KOH/g or less and 0.2 mg KOH/g or more; a process for reducing fine scratches of a substrate, comprising polishing a substrate to be polished with the above-mentioned polishing composition; and a method for manufacturing a substrate, comprising polishing a substrate to be polished with the above-mentioned polishing composition. The polishing composition can be suitably used for final polishing memory hard disk substrates and polishing semiconductor elements.

What is claimed:  
     
         1 . A polishing composition comprising an abrasive having an average primary particle size of 200 nm or less, an oxidizing agent, an acid having a pK1 of 2 or less and/or a salt of an acid having as pK1 of 2 or less, and water, wherein the acid having a pK1 of 2 or less and/or the salt of an acid having a pK1 of 2 or less is selected from the group consisting of sulfurous acid, persulfuric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, tripolyphosphoric acid and amide sulfuric acid, and wherein the acid value (Y) of the polishing composition is 20 mg KOH/g or less and 0.2 mg KOH/g or more.  
     
     
         2 . The polishing composition according to  claim 1 , wherein the polishing composition has an acid value (Y) in the range 0.2 mg KOH/g through 5 mg KOH/g.  
     
     
         3 . The polishing composition of  claim 1  or  2 , wherein the acid value (Y) of the polishing composition satisfies the formula (1):  
         Y ( mg  KOH/ g )≦5.7×10 −17   ×X (/ g )+19.45   (1)  
       wherein X is a concentration of the abrasive in the polishing composition on a numerical basis.  
     
     
         4 . A process for reducing the amount of fine scratches imparted to a substrate during a polishing operation, comprising polishing a substrate to be polished with the polishing composition of any one of  claims 1  to  2 .  
     
     
         5 . A process for reducing the amount of fine scratches imparted to a substrate during a polishing operation, comprising polishing a substrate to be polished with the polishing composition of  claim 3 .  
     
     
         6 . A method for manufacturing a substrate, comprising the step of polishing a substrate to be polished during a manufacturing process with the polishing composition of any one of  claims 1  to  2 .  
     
     
         7 . A method for manufacturing a substrate, comprising the step of polishing a substrate to be polished during a manufacturing process with the polishing composition of  claim 3.