The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 08, 2022

Filed:

Feb. 12, 2021
Applicant:

Kla Corporation, Milpitas, CA (US);

Inventors:

Xuefeng Liu, San Jose, CA (US);

Jenn-Kuen Leong, San Jose, CA (US);

Daniel Kavaldjiev, San Jose, CA (US);

John Fielden, Los Altos, CA (US);

Assignee:

KLA Corporation, Milpitas, CA (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N 21/95 (2006.01); H01L 21/66 (2006.01); G01N 21/21 (2006.01); G01N 21/956 (2006.01); G01N 21/88 (2006.01);
U.S. Cl.
CPC ...
G01N 21/9501 (2013.01); G01N 21/21 (2013.01); G01N 21/956 (2013.01); H01L 22/12 (2013.01); G01N 2021/8822 (2013.01);
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.


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