Safe method for etching silicon dioxide
US5268069A · kind A · utility
33Cited by
10References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1992 |
| Grant date | Dec 7, 1993 |
| Priority date | — |
| Expiry date | Jun 8, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Anhydrous ammonium fluoride is used as a safe source of hydrogen fluoride for etching native or other silicon dioxide layers from silicon substrates. Heating the anhydrous ammonium fluoride above its sublimation temperature results in the generation of hydrogen fluoride gas which etches the silicon dioxide. Controlled amounts of water vapor are used during the etch reaction to ensure complete etching of the thin oxide layers down to within hundredths of a monolayer and to achieve precise etch rate control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.