Patent ID: 8064038

Claim:
An inspection apparatus for inspecting a sample for anomalies, wherein the apparatus is a nulling imaging ellipsometer, the apparatus comprising: a support structure configured and arranged to support the sample; a radiation system configured and arranged to radiate the sample with a polarized radiation beam, the radiation system being provided with a first polarizer; an adjustable retarder; and a detection system including an adjustable second polarizer; and a detector, wherein the adjustable second polarizer and the adjustable retarder are configured to null a portion of a reflected radiation beam that is reflected from a clean portion of the sample, wherein the detection system is configured and arranged to detect, with the detector, the reflected radiation beam; and, a control system configured and arranged to control a rotation of the first polarizer, the second polarizer, the retarder, or any combination thereof such that, for an image component corresponding to the sample, settings that yield zero intensity on the detector are determined, so as to yield the ellipsometric angles ψ and Δ as functions of time and position on the sample.