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US 12,588,444 B2Granted
Method for forming a semiconductor structure
AssigneeUnited Semiconductor (Xiamen) Co., Ltd.
InventorsJian Liu, Chen Chen, Chin-Chun Huang, Wen Yi Tan, Jinjian Ouyang
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Abstract
The present invention uses the thinned second pad oxide layer as the pad oxide layer for the subsequent shallow trench isolation process. Therefore, it is not necessary to remove the entire pad oxide layer on the substrate surface after the P-type high-voltage ion well thermal drive-in process. The subsequent step of re-growing the pad oxide layer is omitted, thereby simplifying the process complexity.
Claims7
A method for forming a semiconductor structure, comprising:
- providing a substrate having a first device region and a second device region thereon;
- forming a first pad oxide layer on the substrate over the first device region and the second device region, wherein the first pad oxide layer has a first thickness;
- forming a nitride hard mask layer on the first pad oxide layer over the first device region and the second device region;
- removing the nitride hard mask layer from the second device region;
- thermally growing a second pad oxide layer on the substrate within the second device region, wherein the second pad oxide layer has a second thickness that is greater than the first thickness;
- forming an ion well in the substrate within the second device region;
- thinning down the second pad oxide layer to a third thickness;
- removing the nitride hard mask layer from the first device region;
- forming a pad nitride layer on the first pad oxide layer and the second pad oxide layer;
- and
- forming a trench isolation structure in the pad nitride layer, the first pad oxide layer, the second pad oxide layer, and the substrate.
8 more elements
Dependencies are inferred from the claim text.