Patent ID: 6937337
Filing Date: 2005-08-30
Classification: G03F

Abstract:
1. A method for determining alignment error in electronic substrates comprising: providing on a layer of a substrate a first contrasting set of elements forming a first grid pattern having a distance between elements; the first grid pattern having a plurality of grid segments in at least one of the x and y directions; providing nested within at least one of the first grid pattern segments, on the same or different layer of a substrate, a second contrasting set of elements forming a second grid pattern having a distance between elements, the second grid pattern having a plurality of grid segments in the x and y directions, the distance between the second set of elements being less than the distance between the first set of elements; measuring location of the first set of elements in the first grid pattern; determining the center of the first set of elements in the first grid pattern; measuring location of the second set of elements in the second grid pattern; determining the center of the second set of elements in the second grid pattern; comparing the center of the first set of elements and the center of the second set of elements and determining alignment error of the first and second grid patterns.