System and method for lateral shearing interferometry in an inspection tool
US11609506B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 18, 2022 |
| Grant date | Mar 21, 2023 |
| Priority date | — |
| Expiry date | Apr 18, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70033
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for in-situ wave front detection within an inspection system is disclosed. The method includes generating light with a light source and directing the light to a stage-level reflective mask grating structure disposed on a mask stage. The method includes directing light reflected from the stage-level reflective structure to a detector-level mask structure disposed in a plane of a detector and then collecting, with an optical element, light reflected from the detector-level mask structure. The method includes forming a pupil image on the detector and laterally shifting the stage-level reflective mask, with the mask stage, across a grating period of the stage-level reflective mask grating structure to provide phase reconstruction for lateral shearing interferometry. The method includes selectively impinging light reflected from the optical element on the one or more sensors of the detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.