US 11,921,825 B2
System and method for determining target feature focus in image-based overlay metrology
Etay Lavert, Milpitas, CA (US); Amnon Manassen, Haifa (IL); Yossi Simon, Milpitas, CA (US); Dimitry Sanko, Vallejo, CA (US); and Avner Safrani, Misgav (IL)
Assigned to KLA Corporation, Milpitas, CA (US)
Filed by KLA Corporation, Milpitas, CA (US)
Filed on Jan. 16, 2023, as Appl. No. 18/097,438.
Application 18/097,438 is a continuation of application No. 17/060,372, filed on Oct. 1, 2020, granted, now 11,556,738.
Prior Publication US 2024/0020353 A1, Jan. 18, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G06N 20/00 (2019.01); G06F 3/0481 (2022.01); G06F 18/214 (2023.01); G06F 18/24 (2023.01); G06F 18/40 (2023.01); G06N 5/04 (2023.01); G06T 11/00 (2006.01)
CPC G06F 18/40 (2023.01) [G06F 3/0481 (2013.01); G06F 18/214 (2023.01); G06F 18/24 (2023.01); G06N 5/04 (2013.01); G06N 20/00 (2019.01); G06T 11/00 (2013.01); G06T 2200/24 (2013.01)] 21 Claims
OG exemplary drawing
 
12. A method of overlay measurement using one or more through-focus imaging metrology sub-systems, comprising:
receiving a plurality of training images captured at one or more focal positions, one or more of the training images including one or more training features of a training specimen;
generating a machine learning classifier based on the plurality of training images captured at the one or more focal positions;
receiving one or more target feature selections for one or more target overlay measurements corresponding to one or more target features of a target specimen;
determining one or more target focal positions based on the one or more target feature selections using the machine learning classifier;
receiving one or more target images captured at the one or more target focal positions, the one or more target images including the one or more target features of the target specimen; and
determining one or more overlay measurements based on the one or more target images.