Etching method, etching apparatus, and method for manufacturing semiconductor device

Abstract

In order to reliably remove, by wet etching, a compound containing a metal and silicon, e.g., a silicate ( 101 a ) containing hafnium metal, the silicate ( 101 a ) is oxidized and then the oxidized silicate ( 101 a ) is wet-etched.

1 - 20 . (canceled)  
     
     
         21 . A method for manufacturing a semiconductor device, comprising: 
 a step of forming a gate insulating film on a silicon region;    a step of forming a conductive film on the gate insulating film;    a step of forming a gate electrode by dry-etching the conductive film using a mask that covers a gate electrode formation region; and    a step of removing a portion of the gate insulating film outside the gate electrode by wet etching, wherein:    the gate insulating film includes an insulating layer made of a compound containing a metal, silicon and oxygen; and    the step of removing the gate insulating film includes a step of oxidizing the insulating layer and then removing the oxidized insulating layer by wet etching.    
     
     
         22 . The method for manufacturing a semiconductor device of  21 , wherein: 
 the metal is hafnium or zirconium; and    a solution containing fluorine and hydrogen is used as an etchant in the step of removing the insulating layer.    
     
     
         23 . The method for manufacturing a semiconductor device of  21 , wherein: 
 the gate insulating film further includes an oxide film formed on the insulating layer and made of an oxide of a metal of the same kind as the metal; and    the step of removing the gate insulating film includes a step of removing a portion of the oxide film outside the gate electrode by wet etching before oxidizing the insulating layer.    
     
     
         24 - 25 . (canceled)