Metrology system for examining objects with EUV measurement light
US11796926B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 2022 |
| Grant date | Oct 24, 2023 |
| Priority date | — |
| Expiry date | Nov 22, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70775
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A metrology system serves for examining objects with EUV measurement light. An illumination optical unit serves for guiding the EUV measurement light towards the object to be examined. The illumination optical unit has an illumination optical unit stop for prescribing a measurement light intensity distribution in an illumination pupil in a pupil plane of the illumination optical unit. An output coupling mirror serves for coupling a part of the measurement light out of an illumination beam path of the illumination optical unit. The output coupling mirror has a mirror surface which is used to couple out measurement light and has an aspect ratio of a greatest mirror surface extent A longitudinally with respect to a mirror surface longitudinal dimension (x) to a smallest mirror surface extent B longitudinally with respect to a mirror surface transverse dimension (y) perpendicular to the mirror surface longitudinal dimension (x). The aspect ratio A/B is greater than 1.1. The result is a metrology system in which a measurement light throughput is optimized even in the simulation or emulation of an imaging optical unit of a projection exposure apparatus having an image-side numerical aper…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.