Dry etching method
US5310456A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 29, 1991 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | Jul 29, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A dry etching method enabling layers of a variety of silicon based materials, such as polysilicon layer, single crystal silicon layer, metal silicide layer or a polycide film, and an aluminum based material, to be etched anisotropically without the necessity of employing depositive CFC-based gases. The etching gas is selected from a variety of gases composed mainly of sulfur halogenides, such as S.sub.2 F.sub.2, S.sub.2 Cl.sub.2 or S.sub.2 Br.sub.2. These sulfur halogenides yield halogen radicals as the etchant in the plasma, and a variety of ions assisting the radical reaction, while yielding free sulfur S, as a result of dissociation by electrical discharge. Free sulfur then is deposited on the sample wafer etched to display the effect of sidewall protection, while the wafer is controlled to a temperature lower than room temperature. According to the present invention, since sulfur yielded in the gaseous phase is used for sidewall protection, anisotropic processing becomes possible even with a system in which, by reason of the construction of the etching mask, the carbon based polymer derived from the resist material may not be expected to by yielded. The deposited sulfur may be …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.