US 12,271,115 B2
Method to detect a defect on a lithographic sample and metrology system to perform such a method
Toufic Jabbour, Aalen (DE); and Lars Omlor, Pleasanton, CA (US)
Assigned to Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed by Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed on Mar. 2, 2022, as Appl. No. 17/684,913.
Claims priority of provisional application 63/155,887, filed on Mar. 3, 2021.
Claims priority of application No. 102021202823.3 (DE), filed on Mar. 23, 2021.
Prior Publication US 2022/0283513 A1, Sep. 8, 2022
Int. Cl. G03F 7/00 (2006.01); G01N 21/95 (2006.01); G06T 7/00 (2017.01); G01N 21/956 (2006.01)
CPC G03F 7/70591 (2013.01) [G01N 21/9501 (2013.01); G03F 7/7065 (2013.01); G06T 7/001 (2013.01); G01N 2021/95676 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method to detect a defect on a lithographic sample with the following steps:
providing detection light and a detector with at least one sensor pixel,
providing a detection pattern (P) causing a light structure of the detection light being structured at least along a first dimension,
aligning the detection pattern (P) such that the detector is aligned normal to a two-dimensional extension of the light structure,
providing a complementary pattern (P) which has a one-dimensional structure which is complementary to that of the detection pattern (P),
moving the sample relative to the detection pattern (P) while gathering the detection light on the detector,
providing a reference sample without defects or with negligible defects,
moving the reference sample relative to the detection pattern (P) while gathering the detection light on the detector,
decoding a defect localization on the sample by correlation using the complementary pattern (P).