Patent ID: 7190823
Filing Date: 2007-03-13
Classification: G03F

Abstract:
1. An overlay vernier pattern for measuring multi-layer overlay alignment accuracy of a substrate, the substrate comprising a first material layer, a second material layer over the first material layer, and a third material layer over the second material layer, the overlay vernier pattern comprising: a plurality of first alignment marks positioned in the first material layer; a plurality of second alignment marks positioned in the second material layer; and a plurality of third alignment marks positioned in the third material layer; wherein a distance between a first alignment mark and a third alignment mark is compared with another distance between an adjacent first alignment mark and an adjacent third alignment mark to perform a measure of misalignment of the first material layer to the third material layer, and a distance between the third alignment mark and a second alignment mark is compared with another distance between an adjacent third alignment mark and an adjacent second alignment mark to perform a measure of misalignment of the third material layer to the second material layer.