Process for etching oxide using hexafluorobutadiene or related fluorocarbons and manifesting a wide process window
US6602434B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1999 |
| Grant date | Aug 5, 2003 |
| Priority date | — |
| Expiry date | Dec 11, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An oxide etching process, particularly 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. One aspect of the invention uses one of four hydrogen-free fluorocarbons having a low F/C ratio, specifically hexafluorobutadiene (C4F6), octafluoropentadiene (C5F8), hexafluorocyclobutene (C4F6), and hexafluorobenzene (C6F6). At least hexafluorobutadiene has a boiling point below 10° C. and is commercially available. Another aspect of the invention, uses an unsaturated fluorocarbon such as pentafluoropropylene (C3HF5), and trifluoropropyne (C3HF3), both of which have boiling points below 10° C. and are commercially available. The fluorocarbon together with a substantial amount of a noble gas such as argon or xenon 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, one of two two-step etch process is used. In the first, the source and bias power are reduced towards the end of the etch. In the second, the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.