Patent ID: 6822738
Filing Date: 2004-11-23
Classification: G01J,G01N

Abstract:
A spectroscopic ellipsometer for evaluating a sample comprising:a broadband light source generating a beam having wavelengths extending over a range of at least 200 to 800 nm; a polarizer disposed in the path of the light beam; a compensator disposed in the path of the light beam, said compensator for inducing phase retardations in the polarization state of the light beam, said compensator having characteristics other than substantially-non-achromatic so that the amount of phase retardations varies with wavelength, over a range of wavelengths, less than is the case were a substantially-non-achromatic compensator utilized, said compensator being rotated at an angular frequency of &ohgr;; an analyzer that interacts with the light beam after the beam interacts with the sample and with the compensator; a detector that measures the Intensity of the light beam after the interaction with the analyzer at a plurality of wavelengths across the wavelength range of at least 200 to 800 nm; said detector generating a time varying intensity output signal simultaneously comprising 2&ohgr; and 4&ohgr; component signals; and optionally a processor for evaluating the sample based on simultaneous use of the intensity output signal 2&ohgr; and 4&ohgr; components.