Patent ID: 11861824
Assignee: KLA CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An overlay metrology system, comprising:
a controller including one or more processors configured to execute program instructions causing the one or more processors to implement a metrology recipe by:
receiving metrology data associated with a plurality of overlay targets on one or more samples;
generating a reference metric for at least some of the plurality of overlay targets based on the metrology data, wherein the reference metric for a particular one of the plurality of overlay targets is associated with one or more properties of the particular one of the plurality of overlay targets that contributes to overlay error;
classifying the plurality of overlay targets into one or more groups based on the reference metrics calculated for the plurality of overlay targets;
generating a reference image for at least some of the one or more groups;
generating corrected metrology data using the associated reference image for at least some of the one or more groups; and
generating overlay measurements for the plurality of overlay targets based on the corrected metrology data.