Calibration of a radiometric optical monitoring system used for fault detection and process monitoring
US8125633B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 2008 |
| Grant date | Feb 28, 2012 |
| Priority date | — |
| Expiry date | Jan 2, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2003/2866
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention is directed to a system and method for radiometric calibration of spectroscopy equipment utilized in fault detection and process monitoring. Initially, a reference spectrograph is calibrated to a local primary standard (a calibrated light source with known spectral intensities and traceable to a reference standard). Other spectrographs are then calibrated from the reference spectrograph rather than the local primary calibration standard. This is accomplished by viewing a light source with both the reference spectrograph and the spectrograph to be calibrated. The output from the spectrograph to be calibrated is compared to the output of the reference spectrograph and then adjusted to match that output. The present calibration process can be performed in two stages, the first with the spectrographs calibrated to the reference spectrograph and then are fine tuned to a narrow band light source at the plasma chamber. Alternatively, the reference spectrograph can be calibrated to the local primary standard while optically coupled to the plasma chamber. There, the local primary standard calibration light source is temporarily positioned within the plasma chamber, or …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.