Patent ID: 11921825
Assignee: KLA CORPORATION
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 11:
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.