Diffraction order selection for optical metrology simulation

摘要

Using one or more selection criteria, diffraction orders for use in optical metrology simulation utilizing rigorous coupled-wave analysis are selected per wavelength. The diffraction orders selected may be symmetric or asymmetric. In an exemplary embodiment, the selection process utilizes one or more termination criteria. The selection of diffraction orders balances the amount of diffraction information needed for accurate optical metrology profile data determination and the number of calculation steps required for regression or library-based approaches of converting diffraction signals to corresponding structure profiles.