Silicon nitride etching composition and method
Compositions useful for the selective removal of silicon nitride materials relative to polysilicon, silicon oxide materials and/or silicide materials from a microelectronic device having same thereon are provided. The compositions of the invention are particularly useful in the etching of 3D NAND structures.
1. A composition consisting of:
(a) phosphoric acid;
(b) at least one silane chosen from (i) alkylamino alkoxysilanes and (ii) alkylamino hydroxyl silanes, wherein said silane possesses at least one moiety chosen from alkoxy, hydroxyl, and fluoro;
(c) a solvent comprising water;
and optionally
(d) a fluoride compound, provided that the fluoride compound is other than hexafluoro silicic acid;
(e) an alkyl amine or phosphate salt thereof
(f) a surfactant,
(g) a carboxylic acid compound, or
(h) a dissolved silicate.
2. The composition of claim 1 , wherein the phosphoric acid is present in a range of 50 to 95 weight percent, based on the total weight of the composition.
3. The composition of claim 1 , wherein the fluoride compound is present and is chosen from HF and monofluorophosphoric acid.
4. The composition of claim 1 , wherein the fluoride compound is present and is a chosen from cesium fluoride and potassium fluoride.
5. The composition of claim 1 , wherein the fluoride compound is present and is chosen from fluoroboric acid; tetramethylammonium hexafluorophosphate; ammonium fluoride; ammonium bifluoride; quaternary ammonium tetrafluoroborates and quaternary phosphonium tetrafluoroborates having the formula NR′ 4 BF 4 and PR′ 4 BF 4 , respectively, wherein R′ may be the same as or different from one another and is selected from hydrogen, straight-chained, branched, or cyclic C 1 -C 6 alkyl, and straight-chained or branched C 6 -C 10 aryl; tetrabutylammonium tetrafluoroborate (TBA-BF 4 ); and combinations thereof.
6. The composition of claim 1 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by the formula
wherein each X is independently chosen from fluorine, a C 1 -C 8 alkyl group, or a group of the formula —OR, wherein R is hydrogen or a C 1 -C 8 alkyl group, n is an integer of from 1 to 6, and each R 1 is independently chosen from hydrogen, a C 1 -C 8 alkyl group, or a group of the formula C 1 -C 8 alkoxy(CH 2 ) n —.
7. The composition of claim 6 , wherein R is methyl or ethyl.
8. The composition of claim 6 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are chosen from (3-aminopropyl)triethoxy-silane; (3-aminopropyl)silane-triol; 3-aminopropyldimethylethoxysilane; 3-aminopropylmethyldiethoxysilane; and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; (N,N-dimethyl-3-aminopropyl)trimethoxysilane; and 3-aminopropyldimethylfluorosilane.
9. The composition of claim 1 , wherein the alkyl amine or phosphate salt thereof is present and is chosen from a primary, secondary, or tertiary C 1 -C 6 alkylamine or dihydrogen phosphate salt thereof.
10. The composition of claim 1 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by the formula
wherein each X is independently chosen from fluorine, a C 1 -C 8 alkyl group, or a group of the formula —OR, wherein R is hydrogen or a C 1 -C 8 alkyl group, n is an integer of from 1 to 6, y is an integer of from 1 to 6, and wherein z is an integer of from 1 to 6.
11. The composition of claim 10 , wherein R is methyl or ethyl.
12. The composition of claim 10 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are chosen from N-(3-trimethoxysilylpropyl)diethylenetriamine; N-(2-aminoethyl)-3-aminopropyltriethoxy silane; N-(2-aminoethyl)-3-aminopropyl-silane triol; (3-trimethoxysilylpropyl)dethylenetriamine; and N-(6-aminohexyl)aminopropyltrimethoxysilane.
13. The composition of claim 10 , wherein the alkyl amine or phosphate salt thereof is present and is chosen from a primary, secondary, or tertiary C 1 -C 6 alkylamine or dihydrogen phosphate salt thereof.
14. A method for removing silicon nitride from a microelectronic device, said method comprising contacting the microelectronic device with a composition of claim 1 , for sufficient time under sufficient conditions to at least partially remove said silicon nitride material from the microelectronic device.
15. The composition of claim 1 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by the formula
16. The composition of claim 1 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by the formula
17. The composition of claim 1 , wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by formula (I) or (II)
18. A composition consisting of:
(a) phosphoric acid;
(b) N-(2-aminoethyl)-3-aminopropyl-silane-triol or (3-aminopropyl)silane triol;
(c) a solvent comprising water,
and optionally
(d) a fluoride compound, provided that the fluoride compound is other than hexafluoro silicic acid;
(e) an alkyl amine or phosphate salt thereof
(f) a surfactant,
(g) a carboxylic acid compound, or
(h) a dissolved silicate.
19. The composition of claim 18 , wherein the fluoride compound is present and is chosen from HF or monofluorophosphoric acid.
20. The composition of claim 18 , wherein the alkyl amine or phosphate salt thereof is present and is chosen from triethylamine or a dihydrogen phosphate salt thereof.