Structured illumination for contrast enhancement in overlay metrology
US10274425B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2017 |
| Grant date | Apr 30, 2019 |
| Priority date | — |
| Expiry date | May 8, 2037 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Contrast enhancement in a metrology tool may include generating a beam of illumination, directing a portion of the generated beam onto a surface of a spatial light modulator (SLM), directing at least a portion of the generated beam incident on the surface of the SLM through an aperture of an aperture stop and onto one or more target structures of one or more samples, and generating a selected illumination pupil function of the illumination transmitted through the aperture utilizing the SLM in order to establish a contrast level of one or more field images of the one or more target structures above a selected contrast threshold, and performing one or more metrology measurements on the one or more target structures utilizing the selected illumination pupil function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.