Method for forming tungsten structures in a semiconductor
US4925524A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 4, 1989 |
| Grant date | May 15, 1990 |
| Priority date | — |
| Expiry date | Jan 4, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method and system for forming tungsten structures in a semiconductor device which uses a chromium protective layer to protect underlying semiconductor layers during the etching process and a chromium mask layer so that tungsten structures can be formed with high aspect ratios using a reactive ion etching to etch the tungsten with a carbon tetrafluoride oxygen plasma in a reactive ion etcher. Long overetches can be achieved because of the high selectivity of chromium to the carbon tetrafluoride/oxygen plasma. The anisotropic nature of the reactive ion etcher prevents undercut during long overetches of the tungsten to further decrease losses in linewidth or increases in resistance as a result of overetching.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.