US 11,892,769 B2
Method for detecting an object structure and apparatus for carrying out the method
Beat Marco Mout, Aalen (DE); Dirk Seidel, Jena-Leutra (DE); Christoph Husemann, Jena (DE); and Ulrich Matejka, Jena (DE)
Assigned to Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed by Carl Zeiss SMT GmbH, Oberkochen (DE)
Filed on Sep. 11, 2020, as Appl. No. 17/018,072.
Claims priority of application No. 102019213904.3 (DE), filed on Sep. 12, 2019.
Prior Publication US 2021/0081693 A1, Mar. 18, 2021
Int. Cl. G03F 1/84 (2012.01); G03F 7/00 (2006.01)
CPC G03F 1/84 (2013.01) [G03F 7/705 (2013.01); G03F 7/70608 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method for detecting an object structure, comprising the following steps:
illuminating at least one portion of an object with illumination light of an at least partly coherent light source from at least one preferred illumination direction,
recording at least one diffraction image of the illuminated portion by spatially resolved detection of the diffraction intensity of the illumination light, diffracted by the illuminated portion, in a detection plane, and
reconstructing at least one portion of the object structure from the at least one recorded diffraction image by way of an iterative method in which, starting from an iteration start value, an iteration diffraction image of a raw object structure is calculated and the latter is compared to the recorded diffraction image in each iteration step,
wherein the iteration start value is taken by starting from a raw object structure of the object structure to be detected, which is obtained by an iteration start value ascertainment method that is independent of the remaining detection method;
wherein the iteration start value is obtained by a simulation method; and
wherein the iteration start value is selected to accelerate a convergence of the iterative reconstruction.