Process for forming shallow trench isolation
AssigneePowerchip Semiconductor Corp.
InventorShye-Lin Wu
Life of this patent
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Abstract
A process for forming a shallow trench isolation is disclosed. Initially, a gate oxide layer is formed on a substrate, and a silicon nitride, which defines an active area, is then patterned on the gate oxide layer. Next, hemispherical grain silicon is formed on the silicon nitride, the sidewalls of the silicon nitride, and the exposed gate oxide layer. Portions of the gate oxide layer are removed to form oxide islands using the silicon nitride and the hemispherical grain silicon as mask. Thereafter, portions of the substrate are removed using the oxide islands as mask. Finally, the exposed substrate is thermally oxidized to form the field oxide structure of the present invention.
Claims18
A process for forming a trench isolation region in a substrate, said process comprising:
- forming a pad oxide layer on the substrate;
- patterning silicon nitride on said pad oxide layer, said patterned silicon nitride defining an active area;
- forming hemispherical grain silicon on said patterned silicon nitride, on sidewalls of said patterned silicon nitride, and on an exposed portion of pad oxide layer;
- forming a plurality of oxide islands on the portion of the substrate not covered by said patterned silicon nitride by removing portions of said pad oxide layer, said patterned silicon nitride and said hemispherical grain silicon serving as mask;
- removing portions of the substrate, said oxide islands serving as mask;
- and
- oxidizing the resulting exposed substrate.
A process for forming a trench isolation region in a substrate, said process comprising:
- forming a pad oxide layer on the substrate;
- patterning silicon nitride on said pad oxide layer, said patterned silicon nitride defining an active area;
- forming hemispherical grain silicon on said patterned silicon nitride, on sidewalls of said patterned silicon nitride, and on the exposed pad oxide layer;
- forming a plurality of oxide islands on the portions of the substrate not covered by said patterned silicon nitride by removing portions of said pad oxide layer, said patterned silicon nitride and said hemispherical grain silicon serving as mask;
- removing portions of the substrate, said oxide islands serving as mask;
- removing said oxide islands;
- and
- oxidizing the resulting exposed substrate.
Dependencies are inferred from the claim text.