Patent ID: 6449043
Filing Date: 2002-09-10
Classification: G01J,G01N

Abstract:
An ellipsometric method for evaluating a sample comprising the steps of:generating a polychromatic probe beam having wavelengths extending from at least 200 and 800 nm; polarizing the probe beam; inducing phase retardations in the polarization state of the probe beam with a compensator, said compensator being substantially non-achromatic so that the amount of phase retardation varies with wavelength; rotating the compensator at an angular frequency &ohgr;; passing the probe beam through an analyzer after the probe beam interacts with the sample and with the compensator; measuring the intensity of the probe beam after the interaction with the analyzer at a plurality of wavelengths across the range of 200 and 800 nm, and generating an output signal having a 2&ohgr; and a 4&ohgr; component; and evaluating the sample based on the 2&ohgr; and 4&ohgr; components of the output signal.