Tunable process for selectively etching oxide using fluoropropylene and a hydrofluorocarbon
US6183655A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1998 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | Mar 27, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A plasma etch process, particularly applicable to a self-aligned contact etch or other advanced structures requiring high-selectivity to nitride or other non-oxide materials and producing no etch stop. The process is preferably performed in a high-density plasma reactor for etching holes with either high or low aspect rations. In this process, hexafluoropropylene (C.sub.3 F.sub.6) is the principal etching gas and another hydrofluorocarbon such as CH.sub.2 F.sub.2 or C.sub.3 H.sub.2 F.sub.6 is added at least in part for its polymer-forming ability, which increases selectivity of etching oxide to nitride. The process gas also includes a substantial amount of an inactive gas such as argon. The process gas mixture can be balanced between the active etching gas and the polymer former in proportions to optimize selectivity over other materials without the occurrence of etch stop in narrow contact holes and with a wide process window.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.