Etch endpoint detection
US6228277A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1998 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Oct 14, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/334
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The specification describes an interferometric in-situ end point detection technique for plasma etching in which the end point is predicted before any overetching occurs. It is based on the recognition that the wavelength of the monitoring beam can be selected so that only a single interferometric fringe appears before clearing. Knowing there is only one fringe, detection is simplified and the etching process can be terminated while a finite but small thickness of the layer remains. This allows etching partial thicknesses of layers. It also allows a two step etch process wherein the etch chemistry can be changed to a highly selective etch to complete clearing of the layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.