Imaging overlay metrology target and complimentary overlay metrology measurement system

摘要

An exclusion region of interest imaging overlay target includes a self-symmetric target structure including two or more pattern elements, and an additional target structure including two or more pattern elements, wherein each of pattern elements of the additional target structure is contained within a boundary defined by one of the pattern elements of the self-symmetric target structure, wherein the self-symmetric target structure is characterized by a composite exterior region of interest, wherein the composite exterior region of interest is formed by removing two or more exclusion zones corresponding with the pattern elements of the additional target structure from an exterior region of interest encompassing the self-symmetric target structure, wherein each of the pattern elements of the additional target structure is characterized by an interior region of interest, wherein the self-symmetric target structure and the additional target structure are configured to have a common center of symmetry upon alignment.