Multi-wavelength interferometry for defect classification
US11017520B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 2019 |
| Grant date | May 25, 2021 |
| Priority date | — |
| Expiry date | Aug 26, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/10152
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An inspection system may include a controller coupled to a differential interference contrast imaging tool for generating images of a sample based on illumination with two sheared illumination beams. The controller may determine a first defect-induced phase shift based on a first set of images of a defect on the sample with a first selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, determine a second defect-induced phase shift based a second set of images of the defect with a second selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, and classify the defect as a metal or a non-metal based on a comparison of the first phase shift to the second phase shift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.