Moiré scatterometry overlay
US11841621B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 2021 |
| Grant date | Dec 12, 2023 |
| Priority date | — |
| Expiry date | Dec 27, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/706851
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An overlay metrology system may scan a sample including inverted Moiré structure pairs along a scan direction, include an illumination sub-system to illuminate first and second Moiré structures of one of an inverted Moiré structure pair with common mutually coherent illumination beam distributions, and include an objective lens to capture at least +/−1 diffraction orders from sample, where a first pupil plane includes overlapping distributions of the collected light with an interference pattern associated with relative wavefront tilt. The system may also include a diffractive element in the first pupil plane, where one diffraction order associated with the first Moiré structure and one diffraction order associated with the second Moiré structure overlap at a common overlap region in a field plane, and a collection field stop located in the field plane to pass light in the common overlap region and block remaining light and remove the relative wavefront tilt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.