Implant mask reversal process
US4578859A · kind A · utility
12Cited by
10References
28Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 22, 1984 |
| Grant date | Apr 1, 1986 |
| Priority date | — |
| Expiry date | Aug 22, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/942
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A reverse mask is formed after the first ion implantation step by applying a second masking material to at least fill the opening in the first mask layer and removing the second mask material to reveal at least a portion of the first mask layer. The first mask layer is then selectively removed with any superimposed second mask layer material thereon. This forms a truly inverse mask. Second conductivity impurities are then introduced through the inverse mask to form self-aligned complementary wells in a substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.