Model - and parameter choice for the optical metrology

摘要

A process for the selection of a profile model and for the selection of parameters of the profile model for use in the optical metrology of structures in a wafer, said method comprising:a) determining of one or more abort criteria are;b) determining of one or more parameters selection criteria;c) selecting a profile model for use in the optical metrology a structure in a wafer, wherein the profile model a set of geometric parameters, which are connected with dimensions of the structure;d) selecting a set of optimization parameters for the profile model with the use of one or more input diffraction signals and of the one or more parameters selection criteria, wherein the set of optimization parameters from the set of geometric parameters is converted;e) testing of the selected profile model and of the set of optimization parameters against the one or more abort criteria are; andf) performing the steps c, d and e, to the one or more termination criteria are fulfilled.