Dry etch of phosphosilicate glass with selectivity to undoped oxide
US4807016A · kind A · utility
341Cited by
5References
26Claims
0Family size
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Key dates
| Filing date | Nov 20, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Nov 20, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An etchant of PSG (14) or BPSG with high selectivity to substantially undoped oxide (12) includes a fluorine-liberating compound and a fluorine-scavenging compound. The fluorine-liberating compound is preferably a perfluorinated inorganic compound, and the fluorine-scavenging compound is preferably a hydrogen-liberating compound such as hydrogen. A particularly preferred inorganic fluorine-liberating compound is nitrogen trifluoride. In an exemplary embodiment, etch rate ratios of PSG to undoped oxide as high as 11 to 1 were obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.