Film thickness control using spectral interferometry
US6589869B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2002 |
| Grant date | Jul 8, 2003 |
| Priority date | — |
| Expiry date | Apr 23, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for controlling a substrate processing operation such as a plasma etch operation. One embodiment of the method of the present invention forms a plasma within a substrate processing chamber to etch a wafer disposed within the chamber. The plasma emission is used by the process as a broadband light source. During the plasma etch process, a plurality of wavelengths of radiation reflected from the surface of the wafer being etched are measured with a spectrometer. These measurements are then compared using pattern recognition techniques to previous measurements taken during a previous plasma etch operation. Certain embodiments of the invention use principal component analysis (PCA) techniques to perform pattern recognition while other embodiment use programmed neural net pattern recognition techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.