摘要 |
Provided is a method for determining one or more profile parameters of a structure using an optical metrology model, the optical metrology model comprising a profile model, an approximation diffraction model, and a fine diffraction model. A simulated approximation diffraction signal is generated based on an approximation diffraction model of the structure. A set of difference diffraction signals is obtained by subtracting the simulated approximation diffraction signal from each of simulated fine diffraction signals and paired with the corresponding profile parameters. A machine learning system is trained using the pairs of difference diffraction signal and corresponding profile parameters. A measured diffraction signal adjusted by the simulated approximation diffraction signal is input into the trained machine learning system and generates the corresponding profile parameters.
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