US Patent 7273761 Box-in-box field-to-field alignment structure

A lithographic pattern includes a first scribe along an edge of a die region, and a second scribe along an opposing edge of the die region. The first scribe includes at least a first translucent box and a second translucent box. The second scribe includes at least a first opaque box and a second opaque box defined respectively by a first translucent frame and a second translucent frame. When the lithographic pattern is stepped between fields on a wafer, the first translucent box is placed at least partially within the first opaque box, and the second translucent box is placed at least partially within the second opaque box. If a continuous ring is formed from a pair of a translucent box and an opaque box, the fields are aligned at least within an amount equal to the difference between the dimensions of that translucent box and that opaque box divided by 2.