US 12,135,505 B2
Spectrometric metrology systems based on multimode interference and lithographic apparatus
Mohamed Swillam, Wilton, CT (US); Justin Lloyd Kreuzer, Trumbull, CT (US); and Stephen Roux, New Fairfield, CT (US)
Assigned to ASML Holding N.V., Veldhoven (NL)
Appl. No. 18/016,225
Filed by ASML Holding N.V., Veldhoven (NL)
PCT Filed Jun. 29, 2021, PCT No. PCT/EP2021/067910
§ 371(c)(1), (2) Date Jan. 13, 2023,
PCT Pub. No. WO2022/012927, PCT Pub. Date Jan. 20, 2022.
Claims priority of provisional application 63/052,651, filed on Jul. 16, 2020.
Prior Publication US 2023/0273531 A1, Aug. 31, 2023
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/706845 (2023.05) [G03F 7/70233 (2013.01); G03F 7/706849 (2023.05); G03F 7/706851 (2023.05)] 20 Claims
OG exemplary drawing
 
9. A lithographic apparatus comprising:
an illumination system configured to illuminate a pattern of a patterning device;
a projection system configured to project an image of the pattern onto a substrate; and
a metrology system comprising:
a radiation source configured to generate radiation;
an optical element configured to direct the radiation toward a target on the substrate to generate scattered radiation from the target;
a first detector configured to receive a first portion of the scattered radiation and to generate a first detection signal based on the received first portion;
a multimode waveguiding device configured to interfere a second portion of the scattered radiation using modes of the multimode waveguiding device;
a second detector configured to receive the interfered second portion and to generate a second detection signal based on the received interfered second portion; and
a processor configured to:
receive the first and second detection signals;
perform an analysis of the received first portion, the received interfered second portion, and a propagation property of the multimode waveguiding device; and
determine a property of the target based on the analysis.