Metrology methods, devices and computer programs

摘要

A metrology method and an associated metrology device are disclosed. The method comprises measuring a target formed of at least two layers on a substrate by a lithographic process and acquiring measurement data, for example by capturing at least one corresponding pair of non-zero-order diffractions in the image plane. . A simulation of the measurement of the target as defined with respect to the geometrical parameters of the target, the geometrical parameters comprising one or more variable geometrical parameters, is performed, in order to directly reconstruct the values for the one or more variable geometrical parameters, the measurement The difference between the data and the simulation data is minimized.