Systems and methods for evaluating critical dimensions based on diffraction-based overlay metrology

A semiconductor device, comprising:

• a first layer comprising a first set of overlay markings;
• and
• a second layer comprising a second set of overlay markings, the second layer being higher than the first layer,
• wherein:
• the first set of overlay markings comprises a plurality of diffraction gratings, each of the plurality of diffraction gratings having a first period;
• the second set of overlay markings comprises a plurality of diffraction grating clusters, each of the plurality of diffraction grating clusters having a plurality of diffraction grating units, wherein the plurality of diffraction grating units in at least one of the plurality of diffraction grating clusters have the first period and at least one of the plurality of diffraction grating units comprises a plurality of diffraction gratings having a second period that is smaller than the first period;
• and
• a first longitudinal-axis associated with a first diffraction grating of a first diffraction grating unit is oriented parallel to a second longitudinal-axis associated with the first diffraction grating unit and a third longitudinal-axis associated with a second diffraction grating of a second diffraction grating unit is oriented perpendicular to a fourth longitudinal-axis associated with the second diffraction grating unit.