Method of determining a spectral weighting for metrology methods and associated apparatuses

Abstract

Disclosed is a method for determining a spectral weighting for configuring spectral characteristics of broadband measurement illumination. The method comprises obtaining first metrology data comprising metrology data from at least a first proper subset of a plurality of targets on a substrate, respectively for each of a plurality of different illumination conditions; determining a respective first spectral weighting component for each target of at least a second proper subset of targets from said first metrology data, said first spectral weighting component being determined to provide a substantially wavelength independent mean intensity from each respective said target; determining a respective second spectral weighting component for each target of at least the second proper subset of targets from said first metrology data; and determining a respective spectral weighting for each target of at least the second proper subset of targets from said first spectral weighting component and said second spectral weighting component.

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