Semiconductor structures are provided. A semiconductor structure includes a plurality of product regions over a semiconductor substrate, a plurality of alignment regions over the semiconductor substrate, and a plurality of first features formed in a material layer over the semiconductor substrate. Each of the alignment regions is surrounded by four of the product regions of a group, and each of the first features extends across two adjacent product regions in the group. The product regions are disposed in rows and columns of a first array, and the alignment regions are disposed in rows and columns of a second array, and the first and second arrays have a same center point.