US 11,886,125 B2
Method for inferring a local uniformity metric
Simon Gijsbert Josephus Mathijssen, Rosmalen (NL); and Kaustuve Bhattacharyya, Veldhoven (NL)
Assigned to ASML NETHERLANDS B. V., Veldhoven (NL)
Appl. No. 17/800,346
Filed by ASML NETHERLANDS B.V., Veldhoven (NL)
PCT Filed Feb. 2, 2021, PCT No. PCT/EP2021/052376
§ 371(c)(1), (2) Date Aug. 17, 2022,
PCT Pub. No. WO2021/175521, PCT Pub. Date Sep. 10, 2021.
Claims priority of application No. 20160404 (EP), filed on Mar. 2, 2020; and application No. 20161969 (EP), filed on Mar. 10, 2020.
Prior Publication US 2023/0062558 A1, Mar. 2, 2023
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/70625 (2013.01) 20 Claims
OG exemplary drawing
 
1. A method of inferring a value for at least one local uniformity metric relating to a product structure, the method comprising:
obtaining intensity data comprising an intensity image relating to at east one diffraction order obtained from a measurement on a target;
obtaining at least one intensity statistical distribution from the intensity image;
determining, from the at least one intensity statistical distribution, an intensity indicator expressing a variation of either a) intensity over the at least one diffraction order, or b) a difference in intensity between two complimentary diffraction orders over the intensity image; and
inferring, by a hardware computer, the value for the at least one local uniformity metric from the intensity indicator.