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US 5,310,457 AGranted
Method of integrated circuit fabrication including selective etching of silicon and silicon compounds
AssigneeAT&T Bell Laboratories
InventorDavid H. Ziger
Life of this patent
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Abstract
High etch selectivity of both silicon nitride and silicon with respect to silicon oxide is obtained using an etch bath of phosphoric acid, hydrofluoric acid, and nitric acid. Minimal loading effects are observed and a long bath life is obtained by replenishing the hydroflouric and nitric acids.
Claims7
A method of semiconductor integrated circuit fabrication comprising the steps of:
- forming a silicon oxide surface;
- forming structures on said, surface said structures comprise layers of both silicon and silicon nitride;
- and
- selectively removing said structures relative to said underlying silicon oxide surface by etching in an etch bath comprising phosphoric acid, hydrofluoric acid, and nitric acid.
1 more element
Dependencies are inferred from the claim text.