Invention Grant
- Patent Title: Sensitive particle detection with spatially-varying polarization rotator and polarizer
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Application No.: US17175179Application Date: 2021-02-12
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Publication No.: US11243175B2Publication Date: 2022-02-08
- Inventor: Xuefeng Liu , Jenn-Kuen Leong , Daniel Kavaldjiev , John Fielden
- Applicant: KLA Corporation
- Applicant Address: US CA Milpitas
- Assignee: KLA Corporation
- Current Assignee: KLA Corporation
- Current Assignee Address: US CA Milpitas
- Agency: Suiter Swantz pc llo
- Main IPC: G01N21/95
- IPC: G01N21/95 ; H01L21/66 ; G01N21/21 ; G01N21/956 ; G01N21/88

Abstract:
A system may include illumination optics to direct an illumination beam to a sample at an off-axis angle, collection optics to collect scattered light from the sample, and a phase mask located at a first pupil plane to provide different phase shifts for light in two or more pupil regions of a collection area to reshape a point spread function of light scattered from one or more particles on a surface of the sample. The system may further include a polarization rotator located at a second pupil plane, where the polarization rotator provides a spatially-varying polarization rotation angle selected to rotate light scattered from the surface of the sample to a selected polarization angle, a polarizer to reject light polarized along the selected polarization angle, and a detector to generate a dark-field image of the sample based on light passed by the polarizer.
Public/Granted literature
- US20210164918A1 SENSITIVE PARTICLE DETECTION WITH SPATIALLY-VARYING POLARIZATION ROTATOR AND POLARIZER Public/Granted day:2021-06-03
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