Etchant and method for fabricating a semiconductor device using the same

Abstract

An etchant for etching at least one of a titanium material and silicon oxide includes a mixed liquid of HCl, NH 4 Fand H 2 O. When the etchant has a NH 4 F/HCl molar ratio of less than one, only the titanium material is etched. When the etchant has a NH 4 F/HCl molar ratio of more than one, only silicon oxide is etched. When the etchant has a NH 4 F/HCl molar ratio of one, the titanium material and silicon oxide are etched at the same rate.

What is claimed is:  
     
         1 . An etchant for etching at least one of a titanium material and silicon oxide, comprising a mixed liquid of HCl, NH 4 F and H 2 O.  
     
     
         2 . An etchant according to  claim 1 , having a NH 4 F/HCl molar ratio of less than one.  
     
     
         3 . A method for fabricating a semiconductor device, comprising the step of: 
 etching a titanium material layer formed on a silicon oxide layer using an etchant according to  claim 2 .    
     
     
         4 . An etchant according to  claim 1 , having a NH 4 F/HCl molar ratio of more than one.  
     
     
         5 . A method for fabricating a semiconductor device, comprising the step of: 
 etching a silicon oxide layer formed on a titanium material layer using an etchant according to  claim 4 .    
     
     
         6 . An etchant according to  claim 1 , having a NH 4 F/HCl molar ratio of substantially one.  
     
     
         7 . A method for fabricating a semiconductor device, comprising the step of: 
 etching a lamination including a titanium material layer and a silicon oxide layer using an etchant according to  claim 6.