Self aligned contact etch using difluoromethane and trifluoromethane
US5965035A · kind A · utility
25Cited by
2References
9Claims
0Family size
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Key dates
| Filing date | Oct 23, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Oct 23, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76804
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An oxide etch process that is highly selective to nitride, thereby being beneficial for a self-aligned contact etch of silicon dioxide to an underlying thin layer of silicon nitride. The process uses difluoromethane (CH.sub.2 F.sub.2) for its strong polymer forming and a greater amount of trifluoromethane (CHF.sub.3) for its strong etching, and with a high diluent fraction of argon (Ar). The etch process is performed at a low pressure of about 20 milliTorr in a high-density plasma etching chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.