Shallow trench isolation structures comprising a graded doped sacrificial silicon dioxide material and a method for forming shallow trench isolation structures
US7141486B1 · kind B1 · utility
7Cited by
11References
25Claims
0Family size
Assignee
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Key dates
| Filing date | Jun 15, 2005 |
| Grant date | Nov 28, 2006 |
| Priority date | — |
| Expiry date | Jun 15, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76232
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A shallow trench isolation structure having a negative taper angle. A graded doped sacrificial layer is formed over a semiconductor substrate and etched to form a first trench therein having trench sidewalls that present a negative taper angle. The substrate is also etched to form a second trench therein overlying the first trench. Silicon dioxide fills both the first and the second trenches to form the shallow trench isolation structure, with the silicon dioxide in the first trench exhibiting a negative taper angle to avoid formation of polysilicon stringers during a gate polysilicon deposition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.