Patent ID: 7653174
Filing Date: 2010-01-26
Classification: G01N

Abstract:
1. A method for inspection, comprising: irradiating a sample using an X-ray beam that comprises a central spot having a first diameter and a first incident intensity, and a halo surrounding the central spot and having a second diameter greater than the first diameter and a second incident intensity less than the first incident intensity, in a first irradiation position in which the central spot impinges on a feature on a surface of the sample, the feature having a third diameter, smaller than the second diameter; measuring a first emitted intensity of X-rays emitted from the sample responsively to the X-ray beam in the first irradiation position; shifting at least one of the sample and the X-ray beam so that the X-ray beam irradiates the sample in a second irradiation position in which the central spot is displaced off the feature; measuring a second emitted intensity of X-rays emitted from the sample responsively to the X-ray beam in the second irradiation position; and comparing the first and second emitted intensities in order to determine a property of the feature.