Formulations for high selective silicon nitride etch
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 the reaction product of:
(A) at least one compound selected from:
tetraalkyldisiloxane-silyldiamines and 1,3 bis(n-aminoalkylaminoalkyl)tetraalkylsiloxanes;
(B) phosphoric acid; and
(C) a solvent comprising water,
wherein composition is an etching composition for selectively etching silicon nitride,
wherein the tetraalkyldisiloxane-silyldiamines are compounds having the formula:
wherein each R 1 and each R 2 is independently chosen from C 1 -C 6 alkyl groups, and
wherein the 1,3 bis(n-aminoalkylaminoalkyl) tetraalkylsiloxanes are compounds having the formula:
wherein each n is independently 1, 2, 3, or 4.
2. The composition of claim 1 , further comprising a fluoride compound.
3. The composition of claim 2 , wherein the fluoride compound is chosen from HF and monofluorphosphoric acid.
4. The composition of claim 2 , 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; and combinations thereof.
5. The compound of claim 2 , wherein the fluoride compound is chosen from cesium fluoride and potassium fluoride.
6. The composition of claim 1 , further comprising a primary, secondary, or tertiary C 1 -C 6 alkylamine, C 1 -C 6 alkanolamine, or dihydrogen phosphate salt thereof.
7. The composition of claim 6 , wherein the primary, secondary, or tertiary C 1 -C 6 alkylamine or C 1 -C 6 alkanolamine is chosen from trimethylamine or triethanolamine.
8. The composition of claim 1 , wherein the tetraalkyldisiloxane- silyldiamine is N 1 ,N 1 ,N 3 ,N 3 -tetraethyl- 1,1,3,3-tetramethyl- 1,3-disiloxanediamine.
9. The composition of claim 1 , wherein the 1,3 bis(n-aminoalkylaminoalkyl) tetraalkylsiloxane is 1,3-bis(2-aminoethylaminomethyl)tetramethyldisiloxane.
10. The composition of claim 1 further comprising an additional compound of the formula:
wherein R 9 is C 1 -C 6 alkyl, R 10 is C 1 -C 6 alkyl or aryl, and R 11 is C 1 -C 6 alkyl or C 2 -C 8 alkenyl.
11. The composition of claim 10 , wherein the additional compound is 1,1,3,3-tetramethoxy-1,3-dimethyldisiloxane.
12. A method for removing silicon nitride from a microelectronic device, said method comprising contacting the microelectronic device with a composition comprising the reaction product of:
(A) at least one compound selected from:
tetraalkyldisiloxane-silyldiamines and
1,3 bis(n-aminoalkylaminoalkyl) tetraalkylsiloxanes;
(B) phosphoric acid; and
(C) a solvent comprising water,
wherein composition is an etching composition for selectively etching silicon nitride,
wherein the tetraalkyldisiloxane-silyldiamines are compounds having the formula:
wherein each R 1 and each R 2 is independently chosen from C 1 -C 6 alkyl groups, and wherein the 1,3 bis(n-aminoalkylaminoalkyl) tetraalkylsiloxanes are compounds having the formula:
wherein each n is independently 1, 2, 3, or 4.