US 12,405,104 B2
Measurement apparatus, method for measuring by interferometry, processing method, optical element and lithography system
Stefan Schulte, Stoedtlen (DE); Vladan Blahnik, Oberkochen (DE); and Martin Peschka, Aalen (DE)
Assigned to CARL ZEISS SMT GMBH, Oberkochen (DE)
Filed by Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed on Jul. 31, 2023, as Appl. No. 18/228,010.
Claims priority of application No. 10 2022 207 884.5 (DE), filed on Jul. 29, 2022.
Prior Publication US 2024/0035811 A1, Feb. 1, 2024
Int. Cl. G01B 9/02017 (2022.01); G01B 9/02 (2022.01); G01B 11/24 (2006.01); G01B 11/30 (2006.01)
CPC G01B 9/02019 (2013.01) [G01B 9/02038 (2013.01); G01B 11/2441 (2013.01); G01B 11/30 (2013.01)] 23 Claims
OG exemplary drawing
 
1. Measurement apparatus for measuring a shape of a surface of a test object by interferometry, comprising:
an illumination device comprising an illumination source configured to generate an illumination wave,
an interferometer device comprising a splitting element configured to split the illumination wave into a test wave, which is directed at the surface and returned as a returning test wave, and into a reference wave, and to combine the returning test wave, which has interacted with the surface being measured, with the reference wave,
a registration device configured to register an interference pattern and evaluate the interference pattern to determine a deviation of the shape of the surface being measured from a target shape,
a control device configured to split the surface being measured into a plurality of individual areas being measured, and
a positioning device configured to position the test wave on the surface being measured such that the individual areas are respectively fully illuminated, wherein:
the registration device is configured to determine, based on data from the individual areas, a deviation of the shape of at least a part of the surface being measured from the target shape, and
the illumination device further comprises at least one adjustable stop device configured to define a subaperture of the interferometer device and to adapt the subaperture to the respective individual areas being measured.