Compositions and methods for the selective removal of silicon nitride
View Patent ↗Compositions useful for the selective removal of silicon nitride materials relative to poly-silicon, silicon oxide materials and/or silicide materials from a microelectronic device having same thereon. The removal compositions include fluorosilicic acid, silicic acid, and at least one organic solvent. Typical process temperatures are less than about 100° C. and typical selectivity for nitride versus oxide etch is about 200:1 to about 2000:1. Under typical process conditions, nickel-based silicides as well as titanium and tantalum nitrides are largely unaffected, and polysilicon etch rates are less than about 1 Å min −1 .
1. A silicon nitride removal composition comprising fluorosilicic acid, silicic acid, at least one corrosion inhibitor, and at least one organic solvent, wherein the source of silicic acid is an alkoxysilane, wherein the at least one organic solvent comprises a glycol, a glycol ether, or a combination thereof, and wherein the molar ratio of fluorosilicic acid to silicic acid is in a range from about 3:1 to about 6:1.
2. The composition of claim 1 , wherein the alkoxysilane comprises a species selected from the group consisting of tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetra-n-propoxysilane, tetrabutoxysilane, aminotriethoxysilane, hexaethoxydisilazane, triethoxychlorosilane, triethoxyfluorosilane, triethoxy(isocyanato)silane, diethoxydichlorosilane, and combinations thereof.
3. The composition of claim 1 , wherein the at least one organic solvent comprises a species selected from the group consisting of ethylene glycol, neopentyl glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether (DPGME), tripropylene glycol methyl ether, propylene glycol monoethyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether (DPGBE), tripropylene glycol n-butyl ether, propylene glycol phenyl ether (phenoxy-2-propanol), and combinations thereof.
4. The composition of claim 1 , wherein said removal composition is suitable for selectively removing silicon nitride material from a microelectronic device wafer having said material thereon.
5. The composition of claim 1 , wherein the at least one corrosion inhibitor comprises a species selected from the group consisting of alkoxylated alkynols, sulfur compounds, nitrogen-containing aromatics, aminocarboxylic acids, phosphonic acids, phosphoric acids, and combinations thereof.
6. The composition of claim 1 , wherein the at least one corrosion inhibitor comprises a species selected from the group consisting of alkoxylated alkynols, ascorbic acid, propargyl alcohol, 2-butene-1,4-diol, 2-butyne-1,4-diol, dimethylglyoxime, thianaphthene, thianthrene, 2-mercaptobenzimidazole (MBI), thiosalicylic acid, benzothiazole, thianthrene-1-boronic acid, mercaptobenzothiazole, thiophene carbonitrile, L-methionine, DL-methionine, L-cysteine, 3-amino-5-mercapto-1,2,4-triazole, 5-amino-1,3,4-thiadiazole-2-thiol, mercaptosuccinic acid, thioctic acid, N-acetyl-L-cysteine, 2-mercapto-1-methylimidazole, 2-mercaptopyridine, 3,3′-thiodipropionic acid, L-cystine, benzotriazole-5-carboxylic acid, imidazole, iminodiacetic acid (IDA), nitrilotris(methylene)triphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenedinitrilotetra(methylenephosphonic) acid (EDTMP), pyrophosphoric acid, salts thereof, and combinations thereof.
7. The composition of claim 1 , further comprising at least one diluent.
8. The composition of claim 7 , wherein the diluent comprises water.
9. The composition of claim 7 , wherein the diluent is combined with a concentrate in a ratio of about 5:1 to about 15:1 to form the removal composition.
10. The composition of claim 7 , wherein the pH is in a range from about 0.5 to about 4.
11. The composition of claim 1 , wherein the composition is substantially devoid of chemical mechanical polishing abrasive material and oxidizing agents.
12. A method of removing silicon nitride from a microelectronic device, said method comprising contacting the microelectronic device with a removal composition for sufficient time under sufficient conditions to at least partially remove said silicon nitride material from the microelectronic device, wherein the removal composition includes fluorosilicic acid, silicic acid, at least one organic solvent, and at least one corrosion inhibitor, wherein the source of silicic acid is an alkoxysilane, wherein the at least one organic solvent comprises a glycol, a glycol ether, or a combination thereof, and wherein the molar ratio of fluorosilicic acid to silicic acid is in a range from about 3:1 to about 6:1.
13. The method of claim 12 , wherein said contacting comprises at least one condition selected from the group consisting of: time of from about 1 minute to about 200 minutes; temperature in a range of from about 40° C. to about 120° C.; and combinations thereof.
14. The method of claim 12 , wherein the alkoxysilane comprises a species selected from the group consisting of tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetra-n-propoxysilane, tetrabutoxysilane, aminotriethoxysilane, hexaethoxydisilazane, triethoxychlorosilane, triethoxyfluorosilane, triethoxy(isocyanato)silane, diethoxydichlorosilane, and combinations thereof.
15. The method of claim 12 , wherein the at least one organic solvent comprises a species selected from the group consisting of ethylene glycol, neopentyl glycol, propylene glycol, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether (DPGME), tripropylene glycol methyl ether, propylene glycol monoethyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether (DPGBE), tripropylene glycol n-butyl ether, propylene glycol phenyl ether (phenoxy-2-propanol), and combinations thereof.
16. The method of claim 12 , wherein the at least one corrosion inhibitor comprises a species selected from the group consisting of alkoxylated alkynols, ascorbic acid, propargyl alcohol, 2-butene-1,4-diol, 2-butyne-1,4-diol, dimethylglyoxime, thianaphthene, thianthrene, 2-mercaptobenzimidazole (MBI), thiosalicylic acid, benzothiazole, thianthrene-1-boronic acid, mercaptobenzothiazole, thiophene carbonitrile, L-methionine, DL-methionine, L-cysteine, 3-amino-5-mercapto-1,2,4-triazole, 5-amino-1,3,4-thiadiazole-2-thiol, mercaptosuccinic acid, thioctic acid, N-acetyl-L-cysteine, 2-mercapto-1-methylimidazole, 2-mercaptopyridine, 3,3′-thiodipropionic acid, L-cystine, benzotriazole-5-carboxylic acid, imidazole, iminodiacetic acid (IDA), nitrilotris(methylene)triphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenedinitrilotetra(methylenephosphonic) acid (EDTMP), pyrophosphoric acid, salts thereof, and combinations thereof.
17. The method of claim 12 , wherein the removal composition further comprises at least one diluent, wherein the at least one diluent comprises water.