Photoresist stripping solution and a method of stripping photoresists using the same

Abstract

A photoresist stripping solution which comprises (a) a salt of hydrofluoric acid with a base free from metal ions, (b) a water-soluble organic solvent, (c) a mercapto group containing corrosion inhibitor, and (d) water, and a method of stripping photoresists with the use of the same are disclosed. In case of using ammonium fluoride as component (a), the photoresist stripping solution may further contain (e) a salt of hydrof luoric acid with a quaternary ammonium hydroxide, such as tetramethylammonium hydroxide, tetrapropylammonium hydroxide, etc., and/or an alkanolamine. The photoresist stripping solution of the present invention has an excellent effect of protecting both Al- and Cu-based metal wiring conductors from corrosion, of efficiently stripping photoresist films and post-ashing residues, and is free from the precipitation of the corrosion inhibitor.

1 . A photoresist stripping solution which comprises (a) a salt of hydrofluoric acid with a base free from metal ions, (b) a water-soluble organic solvent, (c) a mercapto group containing corrosion inhibitor, and (d) water.  
     
     
         2 . The photoresist stripping solution according to  claim 1 , wherein component (a) is ammonium fluoride.  
     
     
         3 . The photoresist stripping solution according to  claim 1 , wherein component (b) is at least one member selected from among dimethylformamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide.  
     
     
         4 . The photoresist stripping solution according to  claim 1 , wherein component (c) is a compound having in its structure a hydroxyl group and/or a carboxyl group at least one of the α- and β- positions.  
     
     
         5 . The photoresist stripping solution according to  claim 1 , wherein component (c) is at least one member selected from among 1-thioglycerol, 3-(2-aminophenylthio)-2-hydroxypropylmercaptan, 3-(2-hydroxyethylthio)-2-hydroxypropylmercaptan, 2-mercaptopropionic acid and 3-mercaptopropionic acid.  
     
     
         6 . The photoresist stripping solution according to  claim 1 , which further contains, in addition to components (a)-(d), with the proviso that component (a) is ammonium fluoride, (e) a salt of hydrofluoric acid with a quaternary ammonium hydroxide represented by the following general formula (I) and/or an alkanolamine:  
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3  and R 4  are each independently an alkyl group or a hydroxyalkyl group having 1 to 4 carbon atoms.  
       
     
     
         7 . The photoresist stripping solution according to  claim 6 , wherein the composition ratio of component (a):component (e) ranges from 2:8 to 8:2 by mass.  
     
     
         8 . A method of stripping photoresists which comprises forming a photoresist pattern on a substrate, etching the substrate using said photoresist as a mask, and thereafter stripping away the photoresist pattern from the substrate using the photoresist stripping solution according to  claim 1 .  
     
     
         9 . A method of stripping photoresists which comprises forming a photoresist pattern on a substrate, etching the substrate using said photoresist as a mask, then plasma ashing the photoresist pattern, and thereafter stripping away post-plasma ashing residues from the substrate using the photoresist stripping solution according to  claim 1 .  
     
     
         10 . The method of stripping photoresists according to  claim 8 , wherein the substrate has either Al wiring conductor or Cu wiring conductor or both thereon.  
     
     
         11 . The method of stripping photoresists according to  claim 8 , wherein the substrate has at least an Si-based interlevel film thereof.  
     
     
         12 . The method of stripping photoresists according to  claim 9 , wherein the substrate has either Al wiring conductor or Cu wiring conductor or both thereon.  
     
     
         13 . The method of stripping photoresists according to  claim 9 , wherein the substrate has at least an Si-based interlevel film thereof.