US 12,086,973 B2
Detection apparatus for simultaneous acquisition of multiple diverse images of an object
Teunis Willem Tukker, Eindhoven (NL); Arie Jeffrey Den Boef, Waalre (NL); Nitesh Pandey, Eindhoven (NL); Marinus Petrus Reijnders, Eindhoven (NL); and Ferry Zijp, Nuenen (NL)
Assigned to ASML Netherlands B.V., Veldhoven (NL)
Appl. No. 17/608,015
Filed by ASML Netherlands B.V., Veldhoven (NL)
PCT Filed Apr. 2, 2020, PCT No. PCT/EP2020/059328
§ 371(c)(1), (2) Date Nov. 1, 2021,
PCT Pub. No. WO2020/229049, PCT Pub. Date Nov. 19, 2020.
Claims priority of application No. 19174102 (EP), filed on May 13, 2019; application No. 19176202 (EP), filed on May 23, 2019; application No. 19179763 (EP), filed on Jun. 12, 2019; and application No. 19195127 (EP), filed on Sep. 3, 2019.
Prior Publication US 2022/0172347 A1, Jun. 2, 2022
Int. Cl. G06T 7/00 (2017.01); G01N 21/47 (2006.01); G02B 5/30 (2006.01); G02B 27/28 (2006.01); G02B 27/42 (2006.01); G03F 7/00 (2006.01)
CPC G06T 7/0004 (2013.01) [G01N 21/4788 (2013.01); G02B 5/3083 (2013.01); G02B 27/283 (2013.01); G02B 27/4205 (2013.01); G03F 7/70616 (2013.01); G03F 7/706851 (2023.05); G06T 2207/10148 (2013.01); G06T 2207/30148 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A metrology apparatus comprising:
a substrate holder configured to hold a substrate comprising a structure;
projection optics configured to project illuminating radiation onto the structure;
a detection apparatus configured to simultaneously acquire multiple images of an object at a plurality of different focus levels and to detect the illuminating radiation subsequent to it having been scattered by the structure, the detection apparatus comprising:
a modulator configured to obtain generate multiple beam copies of an incoming beam;
an optical element configured to impose different phase delays to at least two of the multiple beam copies;
a detector operable to capture the multiple beam copies,
wherein the modulator is configured such that at least two of the multiple beam copies are captured at different focus levels; and
a processor operable to calculate a value for a performance parameter relating to the structure directly from the effect of the performance parameter on a phase of illuminating radiation, as calculated using one or more detected characteristics of the multiple beam copies captured at the different focus levels.