A metrology tool and a method for determining parameters of interest

Abstract

The application provides a metrology tool, and a method, for determining parameters of interest of a structure on an object. This metrology tool comprises: an illumination branch configured for providing an illumination beam; a spectral shaping device for spectrally shaping the illumination beam providing a spectrum comprising at least two disjunct wavelength bands; a controller and a detection branch configured for detecting signals relating to a diffracted beam, the beam comprising diffracted sub-beams, wherein the signals enable determining parameters of interest. The illumination branch is further configured for illuminating the structure on the object which results in the diffracted beam. Each of the diffracted sub-beams is associated with one of the at least two disjunct wavelength bands. The controller is configured for selecting the spectrum allowing distinguishably acquiring the signals from respective diffracted sub-beams and the controller is configured for controllably setting the spectral shaping device to provide the spectrum.

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