System and method for target centering detection in overlay metrology

A system, the system comprising:

• an overlay metrology sub-system configured to acquire one or more images of a sample;
• and
• a controller communicatively coupled to the overlay metrology sub-system, the controller includes one or more processors configured to execute a set of program instructions stored in memory, the set of program instructions configured to cause the one or more processors to:
• receive one or more acquisition images of the sample from the overlay metrology sub-system;
• determine, using a machine learning-based centering model, one or more stage correctables based on the received one or more acquisition images;
• determine, using the machine learning-based centering model, a model output confidence score, wherein the model output confidence score indicates a level of confidence associated with a respective stage correctable determined using the machine learning-based centering model;
• generate one or more control signals configured to cause a sample stage of the overlay metrology sub-system to adjust a stage position based on the determined one or more stage correctables;
• receive one or more measurement images of the sample from the overlay metrology sub-system, wherein the one or more measurement images are acquired by the overlay metrology sub-system based on the adjusted stage position of the sample stage;
• and
• determine one or more overlay measurements based on the received one or more measurement images.

A method comprising:

• receiving one or more acquisition images of a sample from an overlay metrology sub-system;
• determining, using a machine learning-based centering model, one or more stage correctables based on the received one or more acquisition images;
• determining, using the machine learning-based centering model, a model output confidence score, wherein the model output confidence score indicates a level of confidence associated with a respective stage correctable determined using the machine learning-based centering model;
• generating one or more control signals configured to cause a sample stage of the overlay metrology sub-system to adjust a stage position based on the determined one or more stage correctables;
• receiving one or more measurement images of the sample from the overlay metrology sub-system, wherein the one or more measurement images are acquired by the overlay metrology sub-system based on the adjusted stage position of the sample stage;
• and
• determining one or more overlay measurements based on the received one or more measurement images.