Methods for forming a trench isolation structure with rounded corners in a silicon substrate
AssigneeMacronix International Co., Ltd.
InventorsChia-Wei Wu, Jung-Yu Shieh, Ling-Wuu Yang
Life of this patent
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Abstract
A process for forming STI regions comprises performing an In Situ Steam Generation (ISSG) radical conversion on a SiN liner layer within an STI trench in order to expose the top corner of the trench and simultaneously cause rounding the top corner of a liner oxide layer within the trench. The rounding of the liner oxide layer can prevent thinning of a subsequently formed gate oxide.
Claims25
In a semiconductor device comprising a silicon substrate, method for forming an isolation structure, comprising:
- forming a trench in the silicon substrate;
- lining the trench with a liner oxide layer;
- further lining the trench with a silicon nitride layer;
- filling the lined trench with an insulating layer;
- forming a sacrificial oxide layer over the silicon substrate adjacent to the trench using in situ steam generation, wherein the in situ steam generation formation of the oxide layer converts a portion of the silicon nitride layer into silicon dioxide and simultaneously rounds the upper corners of the silicon substrate.
In a semiconductor device comprising a silicon substrate, method for forming an isolation structure, comprising:
- forming a pad oxide layer on the substrate;
- forming a pad mask layer over the pad oxide layer;
- sequentially etching the pad mask layer, the pad oxide layer, and the substrate to form a trench;
- lining the trench with a liner oxide layer;
- further lining the trench with a silicon nitride layer;
- filling the lined trench with an insulating layer;
- forming a sacrificial oxide layer over the silicon substrate adjacent to the trench using in situ steam generation, wherein the in situ steam generation formation of the oxide layer converts a portion of the silicon nitride layer into silicon dioxide and simultaneously rounds the upper corners of the silicon substrate.
Dependencies are inferred from the claim text.