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 comprising:
(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;
(d) a fluoride compound, provided that the fluoride compound is other than hexafluoro silicic acid; and
(e) an alkyl amine or phosphate salt thereof,
wherein the alkylamino alkoxysilane and alkylamino hydroxyl silane compounds are represented by the formulas
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 chosen from HF and monofluorophosphoric acid.
4. The composition of claim 1 , wherein the fluoride compound is chosen from cesium fluoride and potassium fluoride.
5. The composition of claim 1 , wherein the fluoride compound 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 further comprising a surfactant, a carboxylic acid compound, or a dissolved silicate.
7. A composition comprising:
(a) phosphoric acid;
(b) N-(2-aminoethyl)-3-aminopropyl-silane-triol or (3-aminopropyl)silane triol;
(c) a solvent comprising water,
(d) a fluoride compound, provided that the fluoride compound is other than hexafluoro silicic acid; and
(e) an alkyl amine or phosphate salt thereof,
wherein the alkyl amine or phosphate salt thereof is present and is chosen from triethylamine or a dihydrogen phosphate salt thereof.
8. The composition of claim 7 , wherein the fluoride compound is chosen from HF or monofluorophosphoric acid.
9. The composition of claim 7 further comprising a surfactant, a carboxylic acid compound, or a dissolved silicate.