Control of etch rate of silicon dioxide in boiling phosphoric acid
US4092211A · kind A · utility
22Cited by
9References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1976 |
| Grant date | May 30, 1978 |
| Priority date | — |
| Expiry date | Nov 18, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31144
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The etch rate of silicon dioxide, particularly thermally grown silicon dioxide, in boiling phosphoric acid, can be controlled by deliberately adding additional silicate to the acid. For thermally grown silicon dioxide, the etch rate can be reduced from about 5A per minute with no added silicate, to about 0.5A/minute with 1 gram of added silicate to about 1 liter of acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.