Dry etch process for titanium-tungsten films
US5609775A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 17, 1995 |
| Grant date | Mar 11, 1997 |
| Priority date | — |
| Expiry date | Mar 17, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32135
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for dry etching a composite metal film, consisting of an aluminum overlay film, a titanium--tungsten film, and a titanium underlay film, is described. The process uses an organic photoresist as a mask and features improved etch selectivity and non-tapered sidewalls. The addition of CF.sub.4, to the etching chemistry used to pattern titanium--tungsten films, increases the selectivity between the photoresist and titanium--tungsten, allowing for thinner resists to be used, and thus finer resolution to be achieved. The introduction of N2 to the etching chemistry results in a N.sub.2 containing polymer to be formed during the etching procedure, on the sidewalls of the etched structure. The polymer prevents the isotropic component of the reactive ion etching process to attack the metal structure, thus allowing for non-tapered structures to be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.