Patent ID: 8838422
Filing Date: 2014-09-16
Classification: G01B,G01N,G03F

Abstract:
1. A method for controlling a fabrication cluster using an optical metrology system, the optical metrology system including an optical metrology tool, an optical metrology model, and a profile extraction algorithm, the optical metrology model including a model of the optical metrology tool and a profile model of a sample structure, the profile model having profile parameters, the optical metrology tool having an illumination beam and a diffraction beam, the method comprising: (a) using a processor, generating a first library comprising Jones and/or Mueller matrices or components (JMMOC) and corresponding profile parameters, the library generated using ray tracing based on a set of rays, a selected representative ray and a first set of beam propagation parameters; (b) using the processor, generating a first difference library comprising difference JMMOC for each ray of the set of rays, each difference JMMOC calculated by subtracting the JMMOC of each ray of the set of rays from the JMMOC of the selected representative ray; (c) obtaining a measured diffraction signal off the sample structure using the optical metrology tool; and (d) using the processor, regenerating the JMMOC of the representative ray using the first library and regenerating the JMMOC of each ray of the set of rays using the first difference library; (e) obtaining a simulated diffraction signal of the sample structure using the regenerated JMMOC of the representative ray, the regenerated JMMOC of the rays, and the optical metrology model; (f) determining one or more profile parameters of the sample structure using the measured diffraction signal, the simulated diffraction signal, and a matching algorithm; (g) transmitting the one or more profile parameters to a fabrication cluster, the fabrication cluster having process parameters and equipment settings; and (h) adjusting at least one process parameter and/or equipment setting of the fabrication cluster based on the one or more profile parameters.