Rapid thermal nitridized oxide locos process
US4764248A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1987 |
| Grant date | Aug 16, 1988 |
| Priority date | — |
| Expiry date | Apr 13, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/02271
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for minimizing bird's beak in local oxidation of silicon which is compatible with high density (VLSI) semiconductor devices is disclosed. A pad oxide is nitridized using rapid thermal nitridization, which works quickly with minimal thermal cycling of the wafer. A silicon nitride film is then deposited over the nitridized oxide. Both films are exposed to dry plasma etching which gives more consistent results than wet methods. The field oxide is then grown and finally the masking films of the nitridized oxide and silicon nitride are removed, whereby field oxides are grown with minimal bird's beak, and minimal damage to the wafer with a small number of steps. The pad oxide may be grown in the same rapid thermal annealer used for the rapid thermal nitridization. Both cycles (pad oxide growth and nitridization of the pad oxide) can be integrated to "one" cycle and performed sequentially in the same rapid thermal annealer to increase throughput and improve device quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.