Patent ID: 6452671
Filing Date: 2002-09-17
Classification: G01N

Abstract:
An apparatus for inspecting a workpiece having a fine feature pattern formed thereon comprising:rotatable means for supporting said workpiece and rotating said workpiece about an azimuthal angle; and an illuminator having at least one radiation source for directing bright-field illumination in at least two high contrast spectrum regions at said workpiece, wherein at a given azimuthal angle the workpiece diffracts the radiation so that radiation reflected from a defect-free area of the pattern is in a first spectrum region and radiation reflected from a defect in the pattern is in a second spectrum region, and at a different azimuthal angle the workpiece diffracts the radiation so that radiation reflected from a defect-free area of the pattern is in the second spectrum region and radiation reflected from a defect in the pattern is in the first spectrum region.