Patent ID: 7444196
Filing Date: 2008-10-28
Classification: G01N,G03F

Abstract:
1. A method of optimizing diffraction sensitivity of structures in a wafer for optical metrology, the wafer having a patterned structure and an unpatterned structure, the method comprising: a) setting one or more diffraction sensitivity enhancement termination criteria; b) creating a patterned structure on a wafer using one or more fabrication treatment processes, the patterned structure having a treated and an untreated portion; c) applying one or more diffraction sensitivity enhancement techniques to the patterned structure, wherein the one or more diffraction sensitivity enhancement techniques adjust one or more properties of the patterned structure to enhance diffraction contrast between the treated portion and untreated portion of the patterned structure; d) obtaining a first diffraction signal measured off the unpatterned structure on the wafer using an optical metrology device; e) obtaining a second diffraction signal measured off the patterned structure on the wafer using the optical metrology device; f) calculating a diffraction sensitivity enhancement value using the first and second diffraction signals; and g) comparing the calculated diffraction sensitivity enhancement values to the set one or more diffraction sensitivity enhancement termination criteria.