Method of etching a deep trench having a tapered profile in silicon
US6849554B2 · kind B2 · utility
13Cited by
12References
34Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 1, 2002 |
| Grant date | Feb 1, 2005 |
| Priority date | — |
| Expiry date | May 1, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76232
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed herein is a method of etching deep trenches in a substrate which utilizes the overlying mask structure to achieve a trench having a positive tapered sidewall angle of less than about 88°. The method employs the successive etching of a lateral undercut in the substrate beneath a masking material, while at the same time etching vertically downward beneath the mask. The coordinated widening of the lateral undercut at the top of the trench, while vertically extending the depth of the trench, is designed to provide the desired trench sidewall taper angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.