Optimal determination of an overlay target

A computer-implemented method comprising:

• for each given overlay target of a plurality of different overlay targets suitable to be manufactured on a semiconductor specimen, said given overlay target comprising a plurality of stacked semiconductor layers:
• obtaining design data of the given overlay target;
• using at least part of the design data to simulate image data of the given overlay target that would have been acquired by an electron beam examination system;
• using the given image data to predict, before actual manufacturing of the given overlay target, one or more given attributes informative of quality of one or more images of the given overlay target after being manufactured according to the design data;
• and
• using the one or more given attributes determined for each given overlay target to select at least one optimal overlay target that is expected to enable the most accurate overlay measurements among the plurality of different overlay targets, wherein the at least one optimal overlay target is usable to be actually manufactured on the semiconductor specimen.

A non-transitory computer readable medium comprising instructions that, when executed by one or more processing circuitries, cause the one or more processing circuitries to perform operations comprising:

• for each given overlay target of a plurality of different overlay targets suitable to be manufactured on a semiconductor specimen, said given overlay target comprising a plurality of stacked semiconductor layers:
• obtaining design data of the given overlay target;
• using at least part of the design data to simulate image data of the given overlay target that would have been acquired by an electron beam examination system;
• using the given image data to predict, before actual manufacturing of the given overlay target, one or more given attributes informative of quality of one or more images of the given overlay target after being manufactured according to the design data;
• and
• using the one or more given attributes determined for each given overlay target to select at least one optimal overlay target that is expected to enable the most accurate overlay measurements among the plurality of different overlay targets, wherein the at least one optimal overlay target is usable to be actually manufactured on the semiconductor specimen.