US 12,379,655 B2
Contaminant identification metrology system, lithographic apparatus, and methods thereof
Andrew Judge, Monroe, CT (US); Ravi Chaitanya Kalluri, Bethel, CT (US); Michal Emanuel Pawlowski, Norwalk, CT (US); James Hamilton Walsh, Newtown, CT (US); and Justin Lloyd Kreuzer, Trumbull, CT (US)
Assigned to ASML Holding N.V., Veldhoven (NL)
Appl. No. 17/918,426
Filed by ASML Holding N.V., Veldhoven (NL)
PCT Filed Apr. 8, 2021, PCT No. PCT/EP2021/059243
§ 371(c)(1), (2) Date Oct. 12, 2022,
PCT Pub. No. WO2021/213813, PCT Pub. Date Oct. 28, 2021.
Claims priority of provisional application 63/015,034, filed on Apr. 24, 2020.
Prior Publication US 2023/0142459 A1, May 11, 2023
Int. Cl. G03F 1/84 (2012.01); G01N 21/47 (2006.01); G01N 21/88 (2006.01); G01N 21/94 (2006.01); G03F 7/20 (2006.01)
CPC G03F 1/84 (2013.01) [G01N 21/4795 (2013.01); G01N 21/8806 (2013.01); G01N 21/8851 (2013.01); G01N 21/94 (2013.01); G03F 7/2004 (2013.01); G01N 2021/8896 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An inspection system comprising:
an illuminator that generates a first illumination beam at a first wavelength and a second illumination beam at a second wavelength, the first wavelength being different from the second wavelength, and irradiates an object simultaneously with the first illumination beam and the second illumination beam;
a detector that receives radiation scattered by a particle present at a surface of the object at the first wavelength and generates a detection signal; and
processing circuitry configured to:
acquire a first image based on a first intensity of the detection signal at the first wavelength;
acquire a second image based on a second intensity of a second detection signal acquired at the second wavelength;
determine a third image by comparing the first intensity and the second intensity;
analyze a photothermal modulation of Mie scattering of the detection signal at the first wavelength; and
determine a material type of the particle based on the analyzing;
wherein the first wavelength is in the visible spectrum and the second wavelength is in the infrared spectrum.