Photoemission monitoring of EUV mirror and mask surface contamination in actinic EUV systems
US9453801B2 · kind B2 · utility
1Cited by
27References
18Claims
0Family size
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Key dates
| Filing date | May 21, 2013 |
| Grant date | Sep 27, 2016 |
| Priority date | — |
| Expiry date | Feb 5, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2223/652
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Photoelectron emission mapping systems for use with EUV (extreme ultraviolet) mask inspection and lithography systems are described. The mapping systems may be used to provide photoelectron emission maps for EUV photolithography masks and/or EUV mirrors. The systems use EUV photoelectron sources used for mask inspection or photolithography to impinge EUV light on the masks and/or mirrors. The EUV light generates photoelectron on the surfaces of the mask and/or mirrors and the photoelectrons are collected and analyzed by detectors placed away from optical spaces of the EUV chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.