Patent ID: 7171284

Claim:
A method of evaluating optimization of an optical metrology model for use in measuring a wafer structure, the method comprising: a) developing an optical metrology model, the optical metrology model having metrology model variables, which includes profile model parameters of a profile model; b) selecting one or more goals for metrology model optimization; c) selecting one or more profile model parameters to be used in evaluating the one or more selected goals; d) selecting one or more metrology model variables to be set to fixed values; e) setting the one or more selected metrology model variables to fixed values; f) setting one or more termination criteria for the one or more selected goals; g) optimizing the optical metrology model using the fixed values for the one or more selected metrology model variables; h) obtaining measurements for the one or more selected profile model parameters using the optimized optical metrology model; and i) determining if the one or more termination criteria are met by the obtained measurements.