Patent ID: 7728976

Claim:
A method of generating a simulated diffraction signal to determine photoresist parameters of a wafer application to fabricate a structure on a wafer using optical metrology, the method comprising: a) obtaining one or more values of one or more photoresist parameters, which characterize behavior of photoresist when the photoresist undergoes processing steps in the wafer application; b) deriving one or more values of one or more profile parameters using the one or more values of the one or more photoresist parameters, wherein the one or more profile parameters characterize one or more geometric features of the structure; c) generating a simulated diffraction signal using the one or more values of the one or more profile parameters, wherein the simulated diffraction signal characterizes behavior of light diffracted from the structure; d) associating the generated simulated diffraction signal with the one or more values of the one or more photoresist parameters; and e) storing the generated simulated diffraction signal, the one or more values of the one or more photoresist parameters, and the association between the generated simulated diffraction signal and the one or more values of the one or more photoresist parameters; wherein the one or more photoresist parameters comprise change of inhibitor concentration, surface inhibition, diffusion during the photoresist baking process, development rate parameters, labile absorptivity, non-labile absorptivity, and/or intrinsic sensitivity of the photoresist.