Patent ID: 7273761

Claim:
A method for determining field-to-field alignment, comprising: exposing a first scribe pattern from a mask on a resist over a scribe lane between a first field and a second field on a wafer, wherein the first scribe pattern comprises: a first outer pattern of a first transmission characteristic defined by a first frame pattern of a second transmission characteristic; a second outer pattern of the first transmission characteristic defined by a second frame pattern of the second first transmission characteristic, wherein the first frame pattern comprises a smaller inner perimeter and a smaller outer perimeter than the second frame pattern; stepping the mask from the first field to the second field; exposing a second scribe pattern from the mask on the resist over the scribe lane, wherein the second scribe pattern comprises: a first inner pattern of the second transmission characteristic; a second inner pattern of the second transmission characteristics, wherein the first inner pattern and the second inner pattern comprise equal outer perimeters; developing portions of the resist over the scribe exposed according to the first outer pattern, the first inner pattern, the second outer pattern, and the second inner pattern; and etching the scribe to form (1) a first ring from the first outer pattern and the first inner pattern, and (2) a second ring from the second outer pattern and the second inner pattern.