Patent ID: 7283236
Filing Date: 2007-10-16
Classification: G03F

Abstract:
1. A marker structure on a substrate, comprising: a plurality of line elements; and a plurality of trench elements; wherein the line elements and trench elements each have a length in a first direction and are arranged in an alternating repetitive sequence in a second direction perpendicular to the first direction, the alternating repetitive sequence having a sequence length, the marker structure having at least one pitch value, the at least one pitch value being the sum of a line width of one line element and a trench width of one trench element, and wherein (i) respective ones of the plurality of line elements have differing widths such that the plurality of line elements has a minimum line width value, a maximum line width value, and at least one intermediate line width value that is greater than the minimum line width value and less than the maximum line width value, (ii) respective ones of the plurality of trench elements have differing widths such that the plurality of trench elements has a minimum trench width value, a maximum trench width value, and at least one intermediate trench width value that is greater than the minimum trench width value and less than the maximum trench width value, and (iii) a duty cycle of respective pairs of lines and trenches being substantially constant over the sequence length of the marker structure such that there is a variation of the at least one pitch value from a minimum pitch value to a maximum pitch value over the sequence length.