Cleaning agent for a semi-conductor substrate

Abstract

This invention relates to a cleaning agent for a semi-conductor substrate, particularly, one having copper wirings on its surface, comprising a nonionic surfactant and a method for cleaning the same. The said cleaning agent and the method have made it possible to control a speed of etching on silicone oxide so as to remove impurities adsorbed on copper wirings and silicone oxide on a surface of a semi-conductor substrate having copper wirings on its surface, such as copper oxides and particles, without causing corrosion or oxidation of copper wirings nor causing roughness on the surface.

1 . A cleaning agent for a semi-conductor substrate, comprising a compound of the general formula [2″]  
       
         
           
           
               
               
           
         
         (wherein R 1  to R 4  are each independently a hydrogen atom, a hydroxy group, or an alkyl having 1 to 10 carbon atoms or a haloalkyl group having 1 to 10 carbon atoms, and r, r′, s and s′ are each independently 0 or an integer and the total of r, r′, s and s′ are 1 to 20) and a quaternary ammonium compound of the general formula [5′]  
         
           
             
             
                 
                 
             
           
         
         (wherein R 6  to R 9  are each independently a lower alkyl group having 1 to 6 carbon atoms or a hydroxy lower alkyl group having 1 to 6 carbon atoms).  
       
     
     
         2 . A cleaning agent according to  claim 1 , wherein R 1  and R 3  are a methyl group and R 2  and R 4  are an isobutyl group.  
     
     
         3 . A cleaning agent according to  claim 1 , wherein the total of r, r′, s and s′ is 1 to 18.  
     
     
         4 . A cleaning agent according to  claim 1 , wherein the compound shown by the general formula [2″] is one selected from the compounds shown by the following formulas [6], [7] and [8]  
       
         
           
           
               
               
           
         
         (wherein the total of [p+p′], [p+q+q′+p′] or [q+q′] is 1 to 20).  
       
     
     
         5 . A cleaning agent according to  claim 1 , wherein the compound shown by the general formula [5] is tetramethylammonium hydroxide or trimethyl-2-hydroxyethylammonium hydroxide.  
     
     
         6 . A cleaning agent according to  claim 1 , wherein a semi-conductor substrate is a semi-conductor substrate having copper wirings on its surface.  
     
     
         7 . A method for cleaning a semi-conductor substrate, comprising treating a surface of a semi-conductor substrate with a cleaning agent claimed in  claim 1 .  
     
     
         8 . A method according to  claim 7 , wherein a semi-conductor substrate is a semi-conductor substrate having copper wirings on its surface.  
     
     
         9 . A semi-conductor substrate obtained by treating a surface of the semi-conductor substrate with a cleaning agent claimed in  claim 1 .  
     
     
         10 . A cleaning agent for a semi-conductor substrate, comprising a compound shown by the general formula [2′]  
       
         
           
           
               
               
           
         
         (wherein R 1  and R 2  are each independently a hydrogen atom, a hydroxy group, an alkyl group or a hydroxyalkyl group, r and s are each independently 0 or a positive integer, and R 5′  is a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group or a group of the general formula [3′]  
         
           
             
             
                 
                 
             
           
         
         in which R 3  and R 4  are each independently a hydrogen atom, a hydroxy group, an alkyl group or a hydroxyalkyl group, and r′ and s′ are each independently 0 or a positive integer, except for a case where r and s are 0 and a case where r′ and s′ are 0) and an N-containing alkaline substance.  
       
     
     
         11 . A cleaning agent for a semi-conductor substrate according to  claim 10 , wherein the N-containing alkaline substance is one selected from the group consisting of ammonia, a primary amine, a secondary amine, a tertiary amine and a quaternary ammonium compound shown by the general formula [5]  
       
         
           
           
               
               
           
         
         (wherein R 6  to R 9  are each independently a hydrocarbon residue which may contain a hydroxy group and M −  is an anion).  
       
     
     
         12 . A cleaning agent according to  claim 10 , wherein the compound of the general formula [2′] is a compound shown by the general formula [2″]  
       
         
           
           
               
               
           
         
         (wherein the symbols have the same meaning as above).  
       
     
     
         13 . A cleaning agent according to  claim 12 , wherein R 1  and R 3  are a methyl group and R 2  and R 4  are an isobutyl group.  
     
     
         14 . A cleaning agent according to  claim 11 , wherein the N-containing alkaline substance is the quaternary ammonium compound shown by the general formula [5].  
     
     
         15 . A cleaning agent according to  claim 11 , wherein the hydrocarbon residue in R 6  to R 9  of the general formula [5] is an alkyl group.  
     
     
         16 . A cleaning agent according to  claim 15 , wherein the alkyl group of R 6  to R 9  are a methyl group.  
     
     
         17 . A cleaning agent according to  claim 12 , wherein the total of r, s, r′ and s′ are 1 to 20.  
     
     
         18 . A cleaning agent according to  claim 17 , wherein the total of r, s, r′ and s′ are 1 to 18.  
     
     
         19 . A cleaning agent according to  claim 14 , wherein the quaternary ammonium compound is tetramethylammonium hydroxide or trimethyl-2-hydroxyethylammonium hydroxide.  
     
     
         20 . A cleaning agent according to  claim 12 , wherein the compound shown by the general formula [2″] is one selected from the compounds shown by the following formulas [6], [7] and [8]  
       
         
           
           
               
               
           
         
         (wherein the total of [p+p′], [p+q+q′+p′] or [q+q′] is 1 to 20).  
       
     
     
         21 . A cleaning agent according to  claim 10 , wherein a semi-conductor substrate is a semi-conductor substrate having copper wirings on its surface.  
     
     
         22 . A method for cleaning a semi-conductor substrate, comprising treating a surface of a semi-conductor substrate with a cleaning agent claimed in  claim 10 .  
     
     
         23 . A method according to  claim 22 , wherein a semi-conductor substrate is a semi-conductor substrate having copper wirings on its surface.  
     
     
         24 . A semi-conductor substrate obtained by treating a surface of the semi-conductor substrate with a cleaning agent claimed in  claim 10 .  
     
     
         25 . A cleaning agent for a semi-conductor substrate having copper wirings on its surface, comprising a nonionic surfactant.  
     
     
         26 . A cleaning agent according to  claim 25 , wherein the cleaning agent is an alkaline solution.  
     
     
         27 . A cleaning agent according to  claim 25 , wherein the cleaning agent further contains an N-containing alkaline substance.  
     
     
         28 . A cleaning agent according to  claim 27 , wherein the N-containing alkaline substance is one selected from the group consisting of ammonia, an primary to tertiary amine and a quaternary ammonium compound.  
     
     
         29 . A cleaning agent according to  claim 25 , wherein the nonionic surfactant is a nonionic surfactant containing a group of —C≡C— in its molecule.  
     
     
         30 . A cleaning agent according to  claim 29 , wherein the nonionic surfactant is a nonionic surfactant containing a group of —C≡C— and a polyoxyalkylene group in its molecule.  
     
     
         31 . A cleaning agent according to  claim 30 , wherein the polyoxyalkylene group is one shown by the general formula [1] 
       HOX—O y   [1] (wherein X is an alkylene group and y is a positive integer).    
     
     
         32 . A cleaning agent according to  claim 31 , wherein the polyoxyalkylene group is a polyoxyethylene group and/or a polyoxypropylene group.  
     
     
         33 . A cleaning agent according to  claim 30 , wherein the nonionic surfactant is one shown by the general formula [2]  
       
         
           
           
               
               
           
         
         (wherein X 1  is a lower alkylene group, n is a positive integer, R 1  and R 2  are each independently a hydrogen atom, a hydroxy group, an alkyl group or a hydroxyalkyl group, and R 5  is a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group or a group shown by the general formula [3]  
         
           
             
             
                 
                 
             
           
         
         (wherein R 3  and R 4  are each independently a hydrogen atom, a hydroxy group, an alkyl group or a hydroxyalkyl group, X 2  is a lower alkylene group, and m is a positive integer).  
       
     
     
         34 . A cleaning agent according to  claim 33 , wherein R 5  is a group shown by the general formula [3] and X 2  in a number of n and X 2  in a number of m are each independently an ethylene group or a propylene group.  
     
     
         35 . A cleaning agent according to  claim 28 , wherein the N-containing alkaline substance is a quaternary ammonium compound shown by the general formula [5]  
       
         
           
           
               
               
           
         
         (wherein R 6  to R 9  are each independently a hydrocarbon residue which may have a hydroxy group, and M −  is an anion).  
       
     
     
         36 . A cleaning agent according to  claim 35 , wherein the quaternary ammonium compound is tetramethylammonium hydroxide or trimethyl-2-hydroethylammonium hydroxide.  
     
     
         37 . A cleaning agent according to  claim 28 , wherein ammonia or the primary to tertiary amine is one shown by the general formula [4]  
       
         
           
           
               
               
           
         
         (wherein R 11 , R 12  and R 13  are each independently a hydrogen atom, a lower alkyl group or a hydroxy lower alkyl group).  
       
     
     
         38 . A method for cleaning a surface of a semi-conductor substrate having copper wiring on its surface, comprising treating a surface of a semi-conductor substrate having copper wirings on its surface with a cleaning agent claimed in  claim 25 .  
     
     
         39 . A method according to  claim 38 , wherein the surface of semi-conductor substrate having copper wirings on its surface is subjected to a mechanical cleaning process in the presence of the cleaning agent.  
     
     
         40 . A method according to any of  claim 38  and  claim 39 , wherein the cleaning agent additionally contains an N-containing alkaline substance.  
     
     
         41 . A method according to  claim 40 , wherein the N-containing alkaline substance is a quaternary ammonium compound.  
     
     
         42 . A semi-conductor substrate having copper wirings on its surface, which is obtained by treating a surface of a semi-conductor substrate having copper wirings on its surface by the method of  claim 38.