Automated calibration methodology for VUV metrology system
US8153987B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 2009 |
| Grant date | Apr 10, 2012 |
| Priority date | — |
| Expiry date | Aug 3, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/335
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A calibration pad having multiple calibration sites is provided. A particular calibration site may be utilized until that particular site has been determined to have become unacceptable for further use, for example from contamination, in which case the calibration processes may then move to use a different calibration site(s) on the calibration pad(s). A variety of techniques may be utilized to provide the determination that a site is no longer acceptable for use. Movement may thus occur over time from site to site for use in a calibration process. A variety of criteria may be established to determine when to move to another site. Though the designation of a site as “bad” may be based upon measured reflectance data, other criteria may also be used. For example, the number of times a site has been exposed to light may be the criteria for designating a site as bad. Alternatively the cumulative exposure of a site may be the criteria. Further, the plurality of calibration sites that are provided on the single calibration pad may be pre-evaluated so as to initially screen out unacceptable calibration sites prior to use. The techniques provided may be utilized in calibration processes wh…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.