Photoresist and post etch residue cleaning solution

Abstract

A process for cleaning a semi-conductor wafer comprising providing etched wafer containing metal pillars, contacting the etched wafer with a cleaning solution, removing the wafer from the cleaning solution, wherein the resulting wafer is substantially free of post etch residues and photoresist residues without etching the metal pillars by the cleaning solution, the cleaning solution comprising: A. a polar aprotic solvent, B. an inorganic base; C. a co-solvent for said inorganic base; D. a unsaturated cycloaliphatic compound having a ring ether group and at least one substituent bearing a primary hydroxyl group; and E. an organic base comprising an amine compound. The wafer containing photoresist residue or post etch residue can be cleaned by contacting the solution in a spray or immersion.

What we claim is: 
     
         1 . A solution to clean a wafer comprising:
 a polar aprotic solvent,   an inorganic base;   a co-solvent for said inorganic base;   a unsaturated cycloaliphatic compound having a ring ether group and at least one substituent bearing a primary hydroxyl group;   an organic base comprising an amine compound; and   a nonionic surfactant bearing at least one ether group,   wherein the solution has a flash point above an operational temperature used to clean the wafer.   
     
     
         2 . The process of  claim 1 , wherein the flash point is at least 80° C. 
     
     
         3 . The process of  claim 1 , wherein the solution has a viscosity of less than 20 centipoise at 25° C. 
     
     
         4 . A process for cleaning a semi-conductor wafer comprising providing etched wafer containing metal pillars, contacting the etched wafer with a cleaning solution, removing the wafer from the cleaning solution, wherein the resulting wafer is substantially free of post etch residues and photoresist residues without etching the metal pillars by the cleaning solution. 
     
     
         5 . The process of  claim 4 , wherein contact is obtained by immersing the wafer into a cleaning solution. 
     
     
         6 . The process of  claim 4 , wherein the solution comprises:
 A. a polar aprotic solvent,   B. an inorganic base;   C. a co-solvent for said inorganic base;   D. a unsaturated cycloaliphatic compound having a ring ether group and at least one substituent bearing a primary hydroxyl group; and   E. an organic base comprising an amine compound.   
     
     
         7 . The process of  claim 4 , wherein the polar aprotic solvent comprises a C 1 -C 4  dialkyl sulfoxide. 
     
     
         8 . The process of  claim 4 , wherein the solution contains less than 3 weight percent pyrrolidone compounds. 
     
     
         9 . The process of  claim 4 , wherein dimethyl sulfoxide is present in an amount within a range of 60 wt. % to 90 wt. %. 
     
     
         10 . The process of  claim 4 , wherein the polar aprotic solvent is a type present in an amount effective to remove:
 (i) uncured polyimide photoresist from a semiconductor wafer and   (ii) polyimide polymer residues that have been subjected to a plasma etching process,   
       at one or more temperatures within a range of 78° C. to 90° C. and within 30 seconds when immersed in the solution. 
     
     
         11 . The process of  claim 4 , wherein the inorganic base comprises a hydroxide of a Group I or Group II metal. 
     
     
         12 . The process of  claim 11 , wherein the inorganic base comprises a hydroxide of a Group I metal. 
     
     
         13 . The process of  claim 11 , wherein the inorganic base comprises potassium hydroxide. 
     
     
         14 . The process of  claim 4 , wherein the solution does not precipitate solids containing the metal of the inorganic base upon heating to 93° C. and within a 4 hour cool down period in ambient conditions. 
     
     
         15 . The process of  claim 4 , wherein the inorganic base comprises potassium hydroxide present in an amount of at least 1.0 wt. % and up to 2.5 wt. %. 
     
     
         16 . The process of  claim 4 , wherein the solution does not contain added lithium hydroxide. 
     
     
         17 . The process of  claim 4 , wherein the co-solvent comprises a glycol ether compound having at least one ether group and at least one hydroxyl group. 
     
     
         18 . The process of  claim 17 , wherein the glycol ether has a molecular weight of less than 150. 
     
     
         19 . The process of  claim 4 , wherein the co-solvent comprises a glycol ether having one ether group and one hydroxyl group. 
     
     
         20 . The process of  claim 4 , wherein the co-solvent comprises ethyleneglycol monomethyl ether, ethyleneglycol monoethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propyleneglycol butyl ether, ethylene glycol monohexyl ether, ethyleneglycol mono-2-ethylbuyl ether, triethyleneglycol monobutyl ether, tetraethyleneglycol monobutyl ether, or tetrapropyleneglycol monobutyl ether. 
     
     
         21 . The process of  claim 4 , wherein the co-solvent comprises 3-methoxybutanol; 3-methyl-3-methoxybutanol; or 3-methyl-1,3-butanediol. 
     
     
         22 . The process of  claim 4 , wherein the co-solvent is present in the solution in an amount of at least 4 wt. % and up to 8 wt. %. 
     
     
         23 . The process of  claim 4 , wherein said unsaturated cycloaliphatic compound comprises a compound represented by the following general formula (X): 
       
         
           
           
               
               
           
         
       
       wherein R14 and R15 are independently hydrogen, a hydroxyl group, or a C1-C8 alkyl group having one or more primary or secondary hydroxyl groups, provided that R14 and R15 are not both hydrogen and are not both hydroxyl groups. 
     
     
         24 . The process of  claim 4 , wherein said unsaturated cycloaliphatic compound comprises tetrahydrofurfuryl alcohol, furfuryl alcohol, or a combination thereof. 
     
     
         25 . The process of  claim 4 , wherein said unsaturated cycloaliphatic compound is effective to remove residues on the tops of solder bumps on a semiconductor wafer subjected to plasma etching. 
     
     
         26 . The process of  claim 4 , wherein the unsaturated cycloaliphatic compound is present in the solution in an amount ranging from 1 wt. % to 8 wt. %. 
     
     
         27 . The process of  claim 4 , wherein the solution comprises:
 A. dimethyl sulfoxide,   B. potassium hydroxide,   C. a co-solvent represented by the following formula (IX):   
       
         
           
           
               
               
           
         
         wherein R1 and R3 are each independently be a hydrogen atom or a C1-C4 alkyl group, and R2 is a C1-C4 alkyl group, 
         D. a cycloaliphatic compound having a furfuryl moiety, 
         E. an alkanolamine, and 
         F. a polyoxyethylene of phenol or an alkylphenol. 
       
     
     
         28 . The process of  claim 4 , wherein the organic base comprises an alkanolamine having at least two carbon atoms, at least one nitrogen atom, and at least one hydroxyl group, the nitrogen atom and hydroxyl group being attached to different carbon atoms. 
     
     
         29 . The process of  claim 4 , wherein the organic base comprises ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, isopropanolamine, or diisopropanolamine. 
     
     
         30 . The process of  claim 4 , wherein the organic base is present in an amount ranging from 1 wt. % to 5 wt. %. 
     
     
         31 . The process of  claim 4 , further comprising a nonionic surfactant. 
     
     
         32 . The process of  claim 4 , wherein the surfactant has a molecular weight of greater than 200 and less than 1000. 
     
     
         33 . The process of  claim 32 , wherein the amount of surfactant is at least 1 wt. % and up to 10 wt. %. 
     
     
         34 . The process of  claim 32 , wherein the surfactant comprises an aromatic ring having at least one substituent, said-substituent containing —(C2H4O)— moieties. 
     
     
         35 . The process of  claim 32  wherein the surfactant comprises a compound having a phenolic ethoxylate moiety. 
     
     
         36 . The process of  claim 32 , wherein the surfactant comprises an aromatic ring having at least one substituent, said substituent containing —(C2H4O) p — moieties, wherein p is an integer within a range of 2 to 8. 
     
     
         37 . The process of  claim 32 , wherein the surfactant comprises an aromatic ring having a first substituent containing —(C2H4O)— moieties and a second substituent comprising a branched or unbranched, saturated or unsaturated, C 1 -C 22  alkyl group. 
     
     
         38 . The process of  claim 4 , wherein the solution contains not more than 2 wt. % water based on the weight of the solution.