Patent ID: 6128089
Filing Date: 2000-10-03
Classification: G03F

Abstract:
A target for measurement of critical dimension bias on a substrate formed by a lithographic process comprising:first, second and third contrasting arrays of elements on a first layer of said substrate, each of said arrays comprising a plurality of spaced parallel elements contrasting with said substrate and extending from a first element to a last element, each of said elements having length and width, ends of the contrasting elements being aligned along parallel lines forming opposite array edges, the length of the contrasting elements comprising the array width, the array edges being measurable by microscopy without resolution of individual elements of the array, said first, second and third arrays being spaced apart in the X-direction; andfourth, fifth and sixth contrasting arrays of elements on a second layer of said substrate, each of said arrays comprising a plurality of spaced parallel elements contrasting with said substrate and extending from a first element to a last element, each of said elements having length and width, ends of the contrasting elements being aligned along parallel lines forming opposite array edges, the length of the contrasting elements comprising the array width, the array edges being measurable by microscopy without resolution of individual elements of the array, said fourth, fifth and sixth arrays being spaced apart in the X-direction,said first, second and third contrasting arrays of elements on said first layer of said substrate being interposed between at least two of said fourth, fifth and sixth contrasting arrays of elements on said second layer of said substrate, said first, second and third contrasting arrays of elements on said first layer of said substrate being non-overlapping with said fourth, fifth and sixth contrasting arrays of elements on said second layer of said substrate,all of said contrasting arrays being visible wherein critical dimension bias in said X-direction may be measured by reference to one edge of one of said arrays with one edge of another of said arrays without resolution of the individual array elements.