Patent ID: 7468794

Claim:
A spectroscopic rotating compensator ellipsometer system comprising a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a sample system, an analyzer, a dispersive optics and at least one detector system which contains a multiplicity of detector elements, said spectroscopic rotating compensator ellipsometer system further comprising at least one compensator(s) positioned at location(s) selected from the group consisting of: before said stage for supporting a sample system; and after said stage for supporting a sample system; and both before and after said stage for supporting a sample system; such that when said spectroscopic rotating compensator ellipsometer system is used to investigate a sample system present on said stage for supporting a sample system, said analyzer and polarizer are maintained essentially fixed in position and at least one of said at least one compensator(s) is caused to continuously rotate while a polychromatic beam of electromagnetic radiation produced by said source of a polychromatic beam of electromagnetic radiation is caused to pass through said polarizer and said compensator(s), said polychromatic beam of electromagnetic radiation being also caused to interact with said sample system, pass through said analyzer and interact with said dispersive optics such that a multiplicity of essentially single wavelengths are caused to simultaneously enter a corresponding multiplicity of detector elements in said at least one detector system; the improvement being that said spectroscopic rotating compensator ellipsometer system further comprises, after a sample system: at least one spatial filter equivalent comprising a focusing lens and an optical fiber oriented such that electromagnetic radiation focused by said focusing lens enters an end of said optical fiber, said spatial filter equivalent serving to attenuate an outer annular region from said electromagnetic beam as it passes therethrough.