Twin well single mask CMOS process
US4584027A · kind A · utility
19Cited by
7References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1984 |
| Grant date | Apr 22, 1986 |
| Priority date | — |
| Expiry date | Nov 7, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/942
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A twin-well process is formed using a single mask and lift-off techniques. The single implant mask is formed and the first well implanted followed by the deposition of a low temperature CVD film and the application of lift-off techniques to remove the mask and the overlying CVD film. The remaining portions of the CVD film provide a second mask which is self-aligned with and is the complement of the original mask. A second implantation then forms the second well. Alternative approaches using a photoresist mask and a composite nitride-photoresist mask structure are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.