Etch process to produce rounded top corners for sub-micron silicon trench applications
US5843846A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1996 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Dec 31, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/30604
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention describes a method for rounding the top corners of a sub-micron trench in a semiconductor device directly after trench formation. In one embodiment of the present invention the etch process uses an etchant made up of a carbon-fluorine gas, an argon gas, and a nitrogen gas. The combination of gases enables the rounding of the top corners of the trench directly after the trench is formed. The combination of the carbon-fluorine and nitrogen gases etch back the silicon nitride and stress relief oxide layers in order to expose the top corners of the trench. As the top corners of the substrate are exposed the nitrogen and argon gases sputter the top corners rounding them as the etch process completes the trench.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.