Patent Document ID: 9291554
Application ID: 14170150
Patent Flag: 1

Claim One:
1. A computer implemented method of evaluating a diffracting structure, the method comprising: providing a scatterometry model of the diffracting structure using an optical metrology system; computing, with the optical metrology system, spectral information for the scatterometry model of the diffracting structure, including: computing background electric or magnetic fields of an environment of the diffracting structure, computing scattered electric or magnetic fields from the diffracting structure using a scattered field formulation based on the computed background fields, and computing spectral information for the scatterometry model of the diffracting structure based on the computed scattered fields; measuring spectral information for the diffracting structure using the optical metrology system, including illuminating the diffracting structure with a light source, and measuring spectral information for the diffracting structure with a detector; comparing the computed spectral information for the scatterometry model with the measured spectral information for the diffracting; and in response to a good model fit based on the comparison between the computed spectral information and the measured spectral information, determining a physical characteristic of the diffracting structure using the scatterometry model of the diffracting structure.