Novel etch back process for tungsten contact/via filling
US5035768A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1990 |
| Grant date | Jul 30, 1991 |
| Priority date | — |
| Expiry date | Jul 30, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/7684
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An etchback process for etching a refractory metal layer formed on a semiconductor substrate with a greatly reduced micro-loading effect. The etch proceeds in three steps. The first step is a uniform etch which utilizes a gas chemistry of SF.sub.6, O.sub.2 and He and proceeds for a predetermined time to remove most of the metal layer. The second step is a very uniform etch which utilizes a gas chemistry of SF.sub.6, Cl.sub.2 and He and proceeds until the endpoint is detected. The endpoint is detected by measurement and integration of the 772 nm and 775 nm lines of Cl. The third step is a timed etch utilizing a gas chemistry of Cl.sub.2 and He which is used as both an overetch to ensure complete removal of the refractory metal film and as a selective etchant to remove an adhesion underlayer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.