Top corner rounding for shallow trench isolation
US6265317A · kind A · utility
130Cited by
8References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 9, 2001 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Jan 9, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for top-corner rounding at the rim of shallow trenches of the type used for STI is described. This is achieved by first forming the trench using a silicon nitride hard mask having a layer of pad oxide between itself and the silicon surface. The silicon nitride is then briefly and selectively etched so that it pulls back from over the trench rim and exposes a small amount of the underlying pad oxide. Rounding by means of sputtering is then effected with the pad oxide serving to protect the underlying silicon until just before rounding takes place. The result is smoothly rounded corners free of facets and overhangs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.