Position metrology apparatus and associated optical elements
US11428925B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 2019 |
| Grant date | Aug 30, 2022 |
| Priority date | — |
| Expiry date | Nov 1, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/7015
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a metrology apparatus comprising an optical element configured to receive at or near a pupil plane of the metrology apparatus, at least first radiation comprising a first higher diffracted order and second radiation comprising a zeroth order resulting from illumination of a metrology target with radiation; and to direct said first radiation and second radiation together in a first direction. The metrology apparatus is further configured to form at least a first image of a first interference pattern, the first interference pattern resulting from interference of said first radiation and second radiation at an image plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.