Reflective lithography mask inspection tool based on achromatic Fresnel optics
US6914723B2 · kind B2 · utility
51Cited by
10References
31Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 29, 2003 |
| Grant date | Jul 5, 2005 |
| Priority date | — |
| Expiry date | Jul 16, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95676
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A mask blank inspection tool includes an AFO having a diffractive lens and a refractive lens formed on a common substrate. The diffractive lens is a Fresnel zone plate and the refractive lens is a refractive Fresnel lens. The AFO is used to image light from a defect particle on a multilayer mask blank or the surface of the multilayer mask blank to a detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.