Silane etching process
US5965463A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Jul 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A low-temperature process for selectively etching oxide with high selectivity over silicon in a high-density plasma reactor. The principal etching gas is a hydrogen-free fluorocarbon, such as C.sub.2 F.sub.6 or C.sub.4 F.sub.8, to which is added a silane or similar silicon-bearing gas, e.g., the monosilane SiH.sub.4. The fluorocarbon and silane are added in a ratio within the range of 2 to 5, preferably 2.5 to 3. The process provides high polysilicon selectivity, high photoresist facet selectivity, and steep profile angles. Selectivity is enhanced by operating at high flow rates. Silicon tetrafluoride may be added to enhance the oxide etching rate. The process may operate at temperatures of chamber parts below 180.degree. C. and even down to 120.degree. C. The process enables the fabrication of a bi-level contact structure with a wide process window.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.