Patent attributes
A product includes a semiconductor substrate, with at least first and second thin-film layers disposed on the substrate and patterned to define a matrix of dies, which are separated by scribe lines and contain active areas circumscribed by the scribe lines. A plurality of overlay targets are formed in the first and second thin-film layers within each of the active areas, each overlay target having dimensions no greater than 10 μm×10 μm in a plane parallel to the substrate. The plurality of overlay targets include a first linear grating formed in the first thin-film layer and having a first grating vector, and a second linear grating formed in the second thin-film layer, in proximity to the first linear grating, and having a second grating vector parallel to the first grating vector.
