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US 12,595,413 B2Granted
Silicon nitride etching compositions and method
AssigneeEntegris, Inc.
InventorsSteven M. Bilodeau, Claudia Yevenes
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Abstract
Provided are compositions and methods for the wet etching of a surface of a microelectronic device substrate which contains surfaces comprising silicon nitride, silicon oxide, and polysilicon. The method of the invention involves a passivation step and a silicon nitride etching step, as more fully described below. The combination of the two steps was found to greatly improve the selectivity of the silicon nitride etching operation in the presence of polysilicon.
Claims9
A composition comprising the reaction product of:
- a. about 20 to about 80 weight percent of sulfuric acid;
- b. about 20 to about 80 weight percent of water;
- c. about 0.01 to about 0.4 weight percent of sulfurous acid;
- d. about 0.1 to about 10 weight percent of nitric acid;
- and optionally
- e. about 0.001 to about 0.1 weight percent of formic acid,
- wherein the composition is substantially free of fluorides.
4 more elements
A composition for passivating a surface consisting of the reaction product of:
- a. about 20 to about 80 weight percent of sulfuric acid;
- b. about 20 to about 80 weight percent of water;
- c. about 0.01 to about 0.4 weight percent of sulfurous acid;
- d. about 0.1 to about 10 weight percent of nitric acid;
- and optionally
- e. about 0.001 to about 0.1 weight percent of formic acid.
3 more elements
Dependencies are inferred from the claim text.