Supercritical fluid cleaning of semiconductor substrates

Abstract

Chemical formulations and methods for removing unwanted material, such as unexposed photoresist, metal oxides, CMP residue, and the like, from semiconductor wafers or other substrates. The formulations utilize a supercritical fluid-based cleaning composition, which may further include (I) co-solvent(s), (II) surfactant(s), (III) chelating agent(s), and/or (IV) chemical reactant(s).

1 . A supercritical fluid-based cleaning formulation useful for removing unwanted material from a surface having such unwanted material thereon, said supercritical fluid-based cleaning formulation comprising at least one co-solvent, and at least one additional active agent, wherein said at least one additional active agent comprises a sub-species selected from the group consisting of an acid, a base, a reducing agent, an oxidizing agent, an HF source, and a fluoride source.  
     
     
         2 . The cleaning formulation according to  claim 1 , comprising supercritical fluid, wherein the supercritical fluid comprises a fluid selected from the group consisting of: carbon dioxide, oxygen, argon, ammonia, and mixtures thereof.  
     
     
         3 . (canceled)  
     
     
         4 . The cleaning formulation according to  claim 1 , wherein said at least one co-solvent comprises a co-solvent selected from the group consisting of: methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone, N-octylpyrrolidone, N-phenylpyrrolidone, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, γ-butyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.  
     
     
         5 . The cleaning formulation according to  claim 1 , further comprising at least one surfactant selected from the group consisting of an anionic, a neutral, a cationic, and a zwitterionic species.  
     
     
         6 . (canceled)  
     
     
         7 . The cleaning formulation according to  claim 1 , further comprising at least one chelating agent selected from the group consisting of polycarboxylic acids, β-diketones, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.  
     
     
         8 . (canceled)  
     
     
         9 . The cleaning formulation according to  claim 1 , wherein said at least one additional active agent comprises an acid selected from the group consisting of perfluorocarboxylic acids, alkyl sulfonic acids, and arl sulfonic acids.  
     
     
         10 . The cleaning formulation according to  claim 1 , wherein the at least one additional active agent comprises a fluoride source selected from the group consisting of R 4 NF, where each R is independently selected from hydrogen, C 1 -C 8  alkyl, and C 6 -C 12  aryl.  
     
     
         11 . The cleaning formulation according to  claim 1 , wherein the at least one additional active agent comprises a reducing agent selected from the group consisting of hydrogen, ammonia, silanes, hydrides and metal hydrides.  
     
     
         12 . The cleaning formulation according to  claim 1 , wherein the at least one additional active agent comprises a base and said base comprises an amine.  
     
     
         13 . The cleaning formulation according to  claim 1 , wherein the at least one additional active agent comprises an oxidizing agent selected from the group consisting of oxygen, ozone, and nitrous oxide.  
     
     
         14 . The cleaning formulation according to  claim 1 , wherein the at least one additional active agent comprises an HF source selected from the group consisting of HF, triethylamine trihydrogen fluoride, and hydrogen fluoride-pyridine.  
     
     
         15 - 33 . (canceled)  
     
     
         34 . A method for fabricating a semiconductor wafer, said method comprising removing unwanted material from the surface of the wafer with a supercritical fluid-based cleaning formulation comprising at least one co-solvent, and at least one additional active agent, wherein said at least one additional active agent comprises a sub-species selected from the group consisting of an acid, a base, a reducing agent, an oxidizing agent, an HF source, and a fluoride source.  
     
     
         35 . The method according to  claim 34 , comprising supercritical fluid, wherein the supercritical fluid comprises a fluid selected from the group consisting of: carbon dioxide, oxygen, argon, ammonia, and mixtures thereof.  
     
     
         36 . The method according to  claim 34 , wherein the unwanted material comprises photoresist, metal oxides, and/or CMP residues.  
     
     
         37 . The method according to  claim 34 , wherein said at least one co-solvent comprises a co-solvent selected from the group consisting of: methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone, N-octylpyrrolidone, N-phenylpyrrolidone, dimethylsulfoxide, sulfolane, catechol, ethyl lactate, acetone, butyl carbitol, monoethanolamine, butyrol lactone, diglycol amine, alkyl ammonium fluoride, γ-butyrolactone, butylene carbonate, ethylene carbonate, and propylene carbonate.  
     
     
         38 . The method according to  claim 34 , wherein the cleaning formulation includes at least one surfactant selected from the group consisting of an anionic, a neutral, a cationic, and a zwitterionic species.  
     
     
         39 . (canceled)  
     
     
         40 . The method according to  claim 34 , wherein the cleaning formulation further comprises at least one chelating agent selected from the group consisting of polycarboxylic acids, β-diketones, substituted dithiocarbamates, malonic acid esters, and polyethylene glycols.  
     
     
         41 . (canceled)  
     
     
         42 . The method according to  claim 34 , wherein said at least one additional active agent comprises an acid selected from the group consisting of perfluorocarboxylic acids, alkyl sulfonic acids, and aryl sulfonic acids.  
     
     
         43 . The method according to  claim 34 , wherein the at least one additional active agent comprises a fluoride source selected from the group consisting of R 4 NF, where each R is independently selected from hydrogen, C 1 -C 8  alkyl, and C 6 -C 12  aryl.  
     
     
         44 . The method according to  claim 34 , wherein the at least one additional active agent comprises a reducing agent selected from the group consisting of hydrogen, ammonia, silanes, hydrides and metal hydrides.  
     
     
         45 . The method according to  claim 34 , wherein the at least one additional active agent comprises a base and said base comprises an amine.  
     
     
         46 . The method according to  claim 34 , wherein the at least one additional active agent comprises an oxidizing agent selected from the group consisting of oxygen, ozone, and nitrous oxide.  
     
     
         47 . The method according to  claim 34 , wherein the at least one additional active agent comprises an HF source selected from the group consisting of HF, triethylamine trihydrogen fluoride, and hydrogen fluoride-pyridine.  
     
     
         48 .- 86 . (canceled)  
     
     
         87 . The cleaning formulation according to  claim 1 , comprising supercritical CO 2 , isopropanol, and ammonium fluoride.  
     
     
         88 .- 91 . (canceled)  
     
     
         92 . A method of fabricating a semiconductor wafer comprising removing photoresist, CMP residue and/or metal oxide substances from a semiconductor wafer having same thereon using the supercritical fluid-based cleaning formulation of  claim 1.