Method to detect a defect on a lithographic sample and metrology system to perform such a method
US12271115B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 2022 |
| Grant date | Apr 8, 2025 |
| Priority date | — |
| Expiry date | Sep 27, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method to detect a defect on a lithographic sample includes the following steps: detection light and a detector having at least one sensor pixel are provided. Further, a detection pattern is provided causing a light structure of the detection light being structured at least along one dimension (1D, x). The detection pattern is aligned such that the detector is aligned normal to an extension (xy) of the light structure. Further, a complimentary pattern is provided having a 1D structure which is complimentary to that of the detection pattern. The sample is moved relative to the detection pattern while gathering the detection light on the detector. Further, a reference sample without defects or with negligible defects is provided. The reference sample also is moved relative to the detection pattern while gathering the detection light on the detector. A defect (S1 to S4) localization on the sample is decoded by correlation using the complementary pattern. Using such defect detection method improves a signal-to-noise ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.