Thin-film metrology using spectral reflectance with an intermediate in-line reference
US7502119B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2007 |
| Grant date | Mar 10, 2009 |
| Priority date | — |
| Expiry date | Jan 29, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8427
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Reflectance systems and methods are described that use information of an intermediate reference signal to continuously monitor, detect and/or compensate for drift in a metrology system. The intermediate reference signal is present regardless of whether a sample is being measured. The reflectance system comprises components including a transmission element coupled to a sample area and a receiver. The transmission element is configured to route signals between components of the system. The signals include an illumination signal, and a sample signal resulting from interaction of the illumination signal with a sample when the sample is present in the sample area. The signals also include the reference signal that results from interaction of the illumination signal with one or more components of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.