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(11)

EP 3 811 141 A1

(12)

(43) Date of publication: 28.04.2021 Bulletin 2021/17 (21) Application number: 19856120.1 (22) Date of filing: 23.08.2019

(51) International Patent Classification (IPC):  G02B 27/00(2006.01) H01L 21/66(2006.01) H01L 21/67(2006.01) G01N 21/95(2006.01) (86) International application number: PCT/US2019/047803 (87) International publication number: WO 2020/046720 (05.03.2020 Gazette 2020/10)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 27.08.2018 US 201862723446 P 06.08.2019 US 201916533366 (71) Applicant: KLA Corporation Milpitas, CA 95035 (US)

(72) Inventors: ZARE, David Jalil San Jose, California 95128 (US) SOTO, Eduardo Patterson, California 95363 (US) WU, I-Fan Fremont, California 94539 (US) WALSH, Joseph Soquel, California 95073 (US) MCKERNAN, Kent San Jose, California 95125 (US) ARMSTRONG, Joseph Fremont, California 94539 (US) DAVIS, Christopher San Rafael, California 94903 (US) ROSE, Garry Livermore, California 94550 (US) KVAMME, Damon Los Gatos, California 95032 (US) BURFEINDT, Bernd Los Gatos, California 95033 (US) EHSANI, Ali San Ramon, California 94582 (US) (74) Representative: FRKelly  27 Clyde Road Dublin D04 F838 Dublin D04 F838 (IE)