Semiconductor device fabrication method

Abstract

The method for fabricating a semiconductor device comprises the step of planarizing the surface of a film-to-be-polished formed over a semiconductor substrate by polishing, with a polishing pad 104 formed of a foam with a plurality of cells 107 incorporated in a base material 105 thereof, the surface being polished with the base material alone while a polishing slurry containing abrasive grains and an additive of a surfactant is being supplied. The film-to-be-polished is polished with the polishing pad of a foam having no shells around the cells, whereby even when a polishing slurry containing the additive of a surfactant is used, the generation of scratches in the surface of the film-to-be-polished can be depressed.

1 . A method for fabricating a semiconductor device comprising the step of planarizing the surface of a film-to-be-polished formed over a semiconductor substrate by polishing, with a polishing pad while a polishing slurry containing abrasive grains and an additive of a surfactant being supplied onto the polishing pad to thereby planarize the surface of the film-to-be-polished, the polishing pad being formed of a foam with a plurality of cells incorporated in a base material thereof, whereby the surface of the film-to-be-polished is polished with only the base material.  
   
   
       2 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the polishing pad is formed of the foam having the plural cells incorporated in the base material without hollow parts mixed therein.    
   
   
       3 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the polishing pad is formed of a single layer of a pad layer formed of the foam.    
   
   
       4 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the polishing pad is formed of a single layer of a pad layer formed of the foam.    
   
   
       5 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the polishing pad includes a first pad layer of the foam, and a second pad layer formed below the first pad layer and formed of a material which is more flexible than the first pad layer.    
   
   
       6 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the polishing pad includes a first pad layer of the foam, and a second pad layer formed below the first pad layer and formed of a material which is more flexible than the first pad layer.    
   
   
       7 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the base material of the polishing pad is polyurethane.    
   
   
       8 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the base material of the polishing pad is polyurethane.    
   
   
       9 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the base material of the polishing pad is polyethylene.    
   
   
       10 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the base material of the polishing pad is polyethylene.    
   
   
       11 . A method for fabricating a semiconductor device according to  claim 1 , further comprising, before the step of planarizing the surface of the film-to-be-polished, the steps of: 
 forming over the semiconductor substrate an insulation film having etching characteristics different from those of the film-to-be-polished;    forming an opening in the insulation film;    etching the semiconductor substrate with the insulation film as a mask to form a trench in the semiconductor substrate; and    forming the film-to-be-polished in the trench and over the insulation film.    
   
   
       12 . A method for fabricating a semiconductor device according to  claim 2 , further comprising, before the step of planarizing the surface of the film-to-be-polished, the steps of: 
 forming over the semiconductor substrate an insulation film having etching characteristics different from those of the film-to-be-polished;    forming an opening in the insulation film;    etching the semiconductor substrate with the insulation film as a mask to form a trench in the semiconductor substrate; and    forming the film-to-be-polished in the trench and over the insulation film.    
   
   
       13 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the abrasive grains are formed of one of cerium oxide and silicon oxide, or a mixture of them.    
   
   
       14 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the abrasive grains are formed of one of cerium oxide and silicon oxide, or a mixture of them.    
   
   
       15 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the average diameter of the plural cells incorporated in the base material is 150 μm or less.    
   
   
       16 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the average diameter of the plural cells incorporated in the base material is 150 μm or less.    
   
   
       17 . A method for fabricating a semiconductor device according to  claim 1 , wherein 
 the additive is poly(ammonium acrylate).    
   
   
       18 . A method for fabricating a semiconductor device according to  claim 2 , wherein 
 the additive is poly(ammonium acrylate).