Etch endpoint detection
US6855567B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 2000 |
| Grant date | Feb 15, 2005 |
| Priority date | — |
| Expiry date | Feb 15, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31122
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for determining an endpoint for etching a layer includes steps of estimating the etch endpoint and, during etch, directing radiant energy at two or more wavelengths onto the layer to be etched, detecting the last intensity maximum reflected at a first wavelength prior to the estimated etch endpoint, and detecting the intensity maximum reflected at a second wavelength first occurring after the last intensity maximum at the first wavelength. Also, a method for determining an endpoint for etching a layer having an approximate initial thickness by steps of, during etch, directing radiant energy at three or more wavelengths onto the layer to be etched; selecting first, second, and third wavelengths; approximating an etch rate from the time interval between a first detected intensity minimum and an adjacent intensity maximum reflected at the third wavelength, estimating an etch endpoint from the approximate initial thickness of the layer and the approximate etch rate; detecting the last intensity maximum reflected at the first wavelength prior to the estimated etch endpoint; and detecting the intensity maximum reflected at the second wavelength first occurring after the last int…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.