Patent ID: 7417750

Claim:
A method of examining structures formed on a semiconductor wafer using consecutive measurements, the method comprising; forming a first structure on a semiconductor wafer; forming a second structure abutting the first structure; measuring a first measured diffraction signal of the first structure using an angle-resolved spectroscopic scatterometer; measuring a second measured diffraction signal of the second structure using the angle-resolved spectroscopic scatterometer, wherein the first and second measured diffraction signals are measured consecutively; comparing the first measured diffraction signal to a first simulated diffraction signal generated using a profile model of the first structure, the profile model having profile parameters that characterize geometries of the first structure and an azimuth angle parameter defining the angle between the plane of incidence beam and direction of periodicity of the first or second structure; determining one or more features of the first structure based on the comparison of the first measured diffraction signal to the first simulated diffraction signal; comparing the second measured diffraction signal to a second simulated diffraction signal generated using the same profile model as the first simulated diffraction signal, wherein the second simulated diffraction signal was generated with the azimuth angle parameter having a value that is about 90 degrees different than the value of the azimuth angle parameter used to generate the first simulated diffraction signal; and determining one or more features of the second structure based on the comparison of the second measured diffraction signal to the second simulated diffraction signal.