Etch process to produce rounded top corners for sub-micron silicon trench applications
AssigneeIntel Corporation
InventorsPhi L. Nguyen, Ralph A. Schweinfurth
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Abstract
The present invention describes a method for rounding the top corners of a sub-micron trench in a semiconductor device directly after trench formation. In one embodiment of the present invention the etch process uses an etchant made up of a carbon-fluorine gas, an argon gas, and a nitrogen gas. The combination of gases enables the rounding of the top corners of the trench directly after the trench is formed. The combination of the carbon-fluorine and nitrogen gases etch back the silicon nitride and stress relief oxide layers in order to expose the top corners of the trench. As the top corners of the substrate are exposed the nitrogen and argon gases sputter the top corners rounding them as the etch process completes the trench.
Claims15
A method for rounding the top corners of a trench in a semiconductor device comprising:
- performing an etch step to round the top corners of said trench while maintaining critical dimension control,
- wherein the etchant used during said etch step comprises:
- a carbon-fluorine gas, an argon gas, and a nitrogen gas,
- such that the top corners of said trench are rounded at the same time said trench is formed.
A method for forming rounded top trench corners in a semiconductor device comprising:
- providing a substrate;
- depositing a silicon nitride layer above said substrate;
- performing an etch step to form said trench and maintain critical dimension control, wherein the etchant used during said etch step comprises:
- a carbon-fluorine gas, an argon gas, and a nitrogen gas,
- wherein said etch step laterally etches said silicon nitride layer exposing the top corners of said trench in said substrate such that said top corners of said trench are rounded at the same time said trench is formed.
Dependencies are inferred from the claim text.