US 12,446,771 B2
2D multi-layer thickness measurement
Bin Cao, Wayne, NJ (US); Zhenguo Wang, Ridgewood, NJ (US); Kinpui Chan, Ridgewood, NJ (US); Zaixing Mao, Tokyo (JP); and Jongsik Kim, Fort Lee, NJ (US)
Assigned to TOPCON CORPORATION, Tokyo (JP)
Filed by TOPCON CORPORATION, Tokyo (JP)
Filed on Jun. 24, 2020, as Appl. No. 16/911,094.
Claims priority of provisional application 62/868,568, filed on Jun. 28, 2019.
Prior Publication US 2020/0405146 A1, Dec. 31, 2020
Int. Cl. A61B 3/10 (2006.01); A61B 3/00 (2006.01); G06T 7/00 (2017.01); G06T 7/62 (2017.01)
CPC A61B 3/101 (2013.01) [A61B 3/0025 (2013.01); A61B 3/102 (2013.01); G06T 7/0012 (2013.01); G06T 7/62 (2017.01); G06T 2207/20056 (2013.01); G06T 2207/30041 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A thickness measurement method, comprising:
obtaining a fringe image of a multilayer object, the multilayer object comprising a thick layer and a thin layer;
transforming the fringe image into reflectance information;
performing a frequency analysis of the reflectance information;
determining a total thickness of the object based on the frequency analysis of the reflectance information;
determining a thickness of the thick layer based on the determined total thickness;
comparing the frequency analysis of the reflectance information to a frequency analysis of a theoretical model of the object; and
determining a thickness of the thin layer based on the comparison,
wherein the determined thicknesses are at the location of the object from which the fringe image was obtained.