Patent ID: 7453577
Filing Date: 2008-11-18
Classification: G01N

Abstract:
1. An inspection apparatus, comprising: a beamsplitter configured to create, from a radiation beam, a first illumination beam and a second illumination beam directed to a planar reference part of a sample and a patterned part of the sample, respectively; a beam detector configured to detect a detection beam, the detection beam comprising a recombination of radiation reflected and/or scattered from the planar reference part and the patterned part and having an elliptical polarization, and the detection comprising a determination of information related to the eccentricity and/or the orientation of the elliptical polarization of the radiation in the detection beam; and a sample table configured to hold the sample and to move with respect to the first and second illumination beams, the sample table configured to move the patterned part and the planar reference part from a first position where the patterned part and the planar reference part, in use, receive the first and second illumination beams, respectively, to be inspected by the first and second illumination beams, to a second position where the patterned part and the planar reference part, in use, receive the second and first illumination beams, respectively, to be inspected by the second and first illumination beams.