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

Abstract

A photoresist stripping solution comprising (a) a specified quaternary ammonium hydroxide, such as tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, methyltributylammonium hydroxide or methyltripropylammonium hydroxide, (b) a water-soluble amine, (c) water, (d) a corrosion inhibitor and (e) a water-soluble organic solvent, the compounding ratio of component (a) to component (b) being in the range of from 1:3 to 1:10 by mass, as well as a method of stripping photoresists using the solution. The stripping solution of the invention assures effective protection of Al, Cu and other wiring metal conductors against corroding as well as efficient stripping of the photoresist film, post-ashing residues such as modified photoresist film and metal depositions. It also assures efficient stripping of Si-based residues and effective protection of the substrate (particularly the reverse side of a Si substrate) from corroding.

1 . A photoresist stripping solution comprising (a) a quaternary ammonium hydroxide of the following general formula (I):  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3  and R 4  are each independently an alkyl group or a hydroxyalkyl group, provided that at least one of R 1 , R 2 , R 3  and R 4  is an alkyl or hydroxyalkyl group having at least 3 carbon atoms, (b) a water-soluble amine, (c) water, (d) a corrosion inhibitor and (e) a water-soluble organic solvent, the compounding ratio of component (a) to component (b) being in the range of from 1:3 to 1:10 by mass.  
     
     
         2 . The photoresist stripping solution according to  claim 1 , wherein component (a) is at least one compound selected from among tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, methyltributylammonium hydroxide and methyltripropylammonium hydroxide.  
     
     
         3 . The photoresist stripping solution according to  claim 1 , wherein component (b) is at least one compound selected from among monoethanolamine, 2-(2-aminoethoxy)ethanol and N-methylethanolamine.  
     
     
         4 . The photoresist stripping solution according to  claim 1 , wherein component (d) is at least one compound selected from among an aromatic hydroxy compound, a benzotriazole-based compound and a mercapto group containing compound.  
     
     
         5 . The photoresist stripping solution according to  claim 4 , wherein the aromatic hydroxy compound is at least one compound selected from among pyrocatechol, pyrogallol and gallic acid.  
     
     
         6 . The photoresist stripping solution according to  claim 4 , wherein the benzotriazole-based compound is a compound represented by the following general formula (II):  
       
         
           
           
               
               
           
         
       
       where R 5  and R 6  are each independently a hydrogen atom, a substituted or unsubstituted C 1 -C 10  hydrocarbon group, a carboxyl group, an amino group, a hydroxy group, a cyano group, a formyl group, a sulfonylalkyl group or a sulfo group; Q is a hydrogen atom, a hydroxy group, a substituted or unsubstituted C 1 -C 10  hydrocarbon group, provided that it may have an amido bond or an ester bond in the structure, an aryl group or a group represented by the following formula (III)  
       
         
           
           
               
               
           
         
       
       where R 7  is a C 1 -C 6  alkyl group; R 8  and R 9  are each independently a hydrogen atom, a hydroxy group or a C 1 -C 6  hydroxyalkyl or alkoxyalkyl group.  
     
     
         7 . The photoresist stripping solution according to  claim 4 , wherein the benzotriazole-based compound is at least one compound selected from among 1-(2,3-dihydroxypropyl)-benzotriazole, 2,2′-{[(4-methyl-1H-benzotriazol-1-yl)methyl]imino}bisethanol and 2,2′-{[(5-methyl-1H-benzotriazol-1-yl)methyl]imino}bisethanol.  
     
     
         8 . The photoresist stripping solution according to  claim 4 , wherein the mercapto group containing compound is 1-thioglycerol.  
     
     
         9 . A method of stripping photoresists comprising forming a photoresist pattern on a substrate, etching the substrate using said photoresist pattern as a mask, and thereafter stripping away the photoresist pattern from the substrate using the photoresist stripping solution according to  claim 1 .  
     
     
         10 . A method of stripping photoresists comprising forming a photoresist pattern on a substrate, etching the substrate using said photoresist pattern 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 .  
     
     
         11 . The method of stripping photoresists according to  claim 9 , wherein the substrate has either Al wiring or Cu wiring or both thereon.  
     
     
         12 . The method of stripping photoresists according to  claim 9 , wherein the substrate has an Si-based interlevel film thereon.  
     
     
         13 . The method of stripping photoresists according to  claim 9 , wherein the substrate is an Si substrate.  
     
     
         14 . The method of stripping photoresists according to  claim 10 , wherein the substrate has either Al wiring or Cu wiring or both thereon.  
     
     
         15 . The method of stripping photoresists according to  claim 10 , wherein the substrate has an Si-based interlevel film thereon.  
     
     
         16 . The method of stripping photoresists according to  claim 10 , wherein the substrate is an Si substrate.