Polishing composition and polishing method

Abstract

A polishing composition of the present invention contains silicon dioxide, an acid, and water. Silicon dioxide is, for example, colloidal silica, fumed silica, or precipitated silica. The acid is, for example, hydrochloric acid, phosphoric acid, sulfuric acid, phosphonic acid, nitric acid, phosphinic acid, boric acid, acetic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, methanesulfonic acid, formic acid, malic acid, gluconic acid, alanine, glycin, lactic acid, hydroxyethylidene diphosphonic acid, nitrilotris(methylene phosphonic acid), or phosphonobutane tricarboxylic acid. The pH of the polishing composition is preferably in the range of 0.5 to 6. The polishing composition can be suitably used in applications for polishing a glass substrate.

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       10 . The method according to  claim 17 , wherein the acid is hydrochloric acid, phosphoric acid, sulfuric acid, phosphonic acid, nitric acid, phosphinic acid, or boric acid.  
   
   
       11 . The method according to  claim 17 , wherein the acid is acetic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, methanesulfonic acid, formic acid, malic acid, gluconic acid, alanine, glycin, lactic acid, hydroxyethylidene diphosphonic acid, nitrilotris(methylene phosphonic acid), or phosphonobutane tricarboxylic acid.  
   
   
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       17 . A method for polishing a glass substrate, the method comprising: 
 preparing a polishing composition comprising silicon dioxide, an acid, and water; and    polishing the surface of a glass substrate, using the prepared polishing composition.    
   
   
       18 . The method for polishing a glass substrate according to  claim 17 , wherein said polishing the surface of a glass substrate comprises: 
 preliminarily polishing the surface of the glass substrate; and    finish-polishing the surface of the preliminarily polished glass substrate, in which    the polishing composition is used in the finish-polishing of the surface of the preliminarily polished glass substrate.    
   
   
       19 . The method for polishing a glass substrate according to  claim 17 , wherein said preparing a polishing composition comprises diluting the polishing composition with water.  
   
   
       20 . The method for polishing a glass substrate according to  claim 19 , wherein the volume of water to be used for dilution of the polishing composition is not more than 50 times as large as the volume of the polishing composition before dilution.  
   
   
       21 . The method according to  claim 1 , wherein the acid is at least one selected from the group consisting of phosphoric acid, pphosphonic acid, phosphinic acid, acetic acid, itaconic acid, methanesulfonic acid, formic acid, hydroxyethylidene diphosphonic acid, nitrilotris (methylene phosphonic acid), and phosphonobutane tricarboxylic acid.