Patent ID: 11880142
Assignee: KLA CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 27:
28. The self-calibrating overlay metrology system of claim 21, wherein generating corrected overlay measurements associated with the selected one of the two or more overlay metrology tools for the plurality of device targets by adjusting the preliminary device overlay measurements based on the self-calibrating assist overlay measurements comprises:
comparing the preliminary device overlay measurements with the self-calibrating assist overlay measurements from the selected one of the two or more overlay metrology tools based on one or more statistical metrics;
generating an additional quality metric associated with the one or more statistical metrics;
correcting the preliminary device overlay measurements to compensate for differences between the one or more statistical metrics if the quality metric is below a selected threshold; and
retraining the overlay recipe using the self-calibrating assist overlay measurements and generating the corrected overlay measurements based on the overlay recipe after retraining if the quality metric is equal to or above a selected threshold.