Patent ID: 7667842
Filing Date: 2010-02-23
Classification: G03F,H01L

Abstract:
1. An overlay measurement structure, comprising: a first periodic structure formed in a first device layer of a specified measurement site formed on a substrate, said first periodic structure comprising a first periodic sub-structure and a second periodic sub-structure, the first and second periodic sub-structures in said first periodic structure each including a plurality of first structure elements, wherein a first subset of the first structure elements comprise segmented structure elements, and a second subset of the first structure elements comprise non-segmented structure elements aligned with said segmented structure elements in said first subset of said first structure elements; and a second periodic structure formed in a second device layer located above said first device layer, said second periodic structure comprising a first periodic sub-structure and a second periodic sub-structure, the first and second periodic sub-structures in said second periodic structure each including a plurality of second structure elements, wherein a first subset of the second structure elements comprise segmented structure elements, and a second subset of the second structure elements comprise non-segmented structure elements aligned with said segmented structure elements in said first subset of said second structure elements, said first and second periodic structures forming a periodic stacked structure in said specified measurement site.