US 12,105,432 B2
Metrology method and associated computer product
Narjes Javaheri, Eindhoven (NL); Maurits Van Der Schaar, Eindhoven (NL); Tieh-Ming Chang, Eindhoven (NL); Hilko Dirk Bos, Utrecht (NL); Patrick Warnaar, Tilburg (NL); Samira Bahrami, Amsterdam (NL); Mohammadreza Hajiahmadi, Den Bosch (NL); Sergey Tarabrin, Eindhoven (NL); and Mykhailo Semkiv, Veldhoven (NL)
Assigned to ASML Netherlands B.V., Veldhoven (NL)
Appl. No. 17/625,640
Filed by ASML Netherlands B.V., Veldhoven (NL)
PCT Filed Jul. 7, 2020, PCT No. PCT/EP2020/069139
§ 371(c)(1), (2) Date Jan. 7, 2022,
PCT Pub. No. WO2021/005067, PCT Pub. Date Jan. 14, 2021.
Claims priority of provisional application 62/871,429, filed on Jul. 8, 2019.
Prior Publication US 2022/0252990 A1, Aug. 11, 2022
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/70633 (2013.01) 20 Claims
OG exemplary drawing
 
1. A method for determining overlay at plural heights of a non-flat, buried metrology target having another metrology target disposed thereon, the method comprising:
measuring radiation reflected by metrology targets;
inferring data of a parameter of the buried metrology target from the measurement as a function of the parameter verses wavelength, which yields a periodical variation of the parameter; and
decomposing the periodical variation of the parameter to isolate the plural heights of the buried metrology target as a function of amplitude verses wavelength.