Patent ID: 7492455

Claim:
A spectroscopic ellipsometer system comprising: a source of a polychromatic beam of electromagnetic radiation; a stage for supporting a sample system; a multi-element spectroscopic detector system; said spectroscopic ellipsometer system further comprising: at least two polarizers (P 1 ) (P 2 ), which remain fixed in position during data acquisition, said polarizers (P 1 ) (P 2 ) being in the source of a beam of polychromatic electromagnetic radiation, before the stage for supporting a sample system; an analyzer, which remains fixed in position during data acquisition, after said stage for supporting a sample system and before said multi-element spectroscopic detector system; and at least one means for discretely, sequentially, modifying a polarization state of a beam of electromagnetic radiation provided by said source of a beam of polychromatic electromagnetic radiation through a plurality of polarization states, said means for discretely, sequentially, modifying a polarization state of a beam of electromagnetic radiation provided by said source of a beam of polychromatic electromagnetic radiation through a plurality of polarization states being present at least one location selected from the group consisting of: between said polarizer and said stage for supporting a sample system; and between said stage for supporting a sample system and said analyzer; and positioned so that said beam of electromagnetic radiation transmits therethrough in use; said ellipsometer system being configured such that a polychromatic beam of electromagnetic radiation provided by said source thereof is directed to interact with a sample system present on said stage for supporting a sample system; said ellipsometer system being distinguished in that said source of a beam of polychromatic electromagnetic radiation comprises: a. at least a first (S 1 ) and a second (S 2 ) source of polychromatic electromagnetic radiation beams, (B 1 ) and (B 2 ) respectively, which have said polarizers, (P 1 ) and (P 2 ) respectively, associated therewith; and b. at least one electromagnetic beam combining (BC 1 ) means comprising an uncoated plate with transmission characteristics that are determined by angle-of-incidence and polarization state of a beam of electromagnetic such that in use one of said (B 1 ) and (B 2 ) beams after passing through its associated polarizer (P 1 ) (P 2 ), passes through said beam combining (BC 1 ) means, and the other thereof, after passing through its associated polarizer (P 2 ) (P 1 ), reflects from said beam combining means (BC 1 ), such that a polarized beam containing wavelengths from at least one of said (S 1 ) and (S 2 ) sources emerges from said beam combining (BC 1 ) means and is directed to interact with said sample system present on said stage for supporting a sample system; said at least first (S 1 ) and second (S 2 ) sources being separately energizable.