Highly selective oxide etch process using hexafluorobutadiene
US6613691B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 2000 |
| Grant date | Sep 2, 2003 |
| Priority date | — |
| Expiry date | Sep 29, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An oxide etching process, particular useful for selectively etching oxide over a feature having a non-oxide composition, such as silicon nitride and especially when that feature has a corner that is prone to faceting during the oxide etch. The invention preferably uses the unsaturated 4-carbon fluorocarbons, specifically hexafluorobutadiene (C4F6), which has a below 10°C. and is commercially available. The hexafluorobutadiene together with argon is excited into a high-density plasma in a reactor which inductively couples plasma source power into the chamber and RF biases the pedestal electrode supporting the wafer. Preferably, a two-step etch is used process is used in which the above etching gas is used in the main step to provide a good vertical profile and a more strongly polymerizing fluorocarbon such as difluoromethane (CH2F2) is added in the over etch to protect the nitride corner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.