Patent ID: 8178838
Filing Date: 2012-05-15
Classification: G01N,H01J

Abstract:
1. A method for generating three dimensional tomographic image data of a sample with a beam of charged particles, the method comprising the steps of: (a) providing on a surface of the sample, marks at selected positions, said selected positions of the marks being indicative of a position on the surface of the sample in a selected direction; (b) removing a slice from said sample by a beam of charged particles scanning across said sample in a direction perpendicular to said selected direction, (c) scanning said sample with a primary charged particle beam, said primary charged particle beam having a direction of propagation not perpendicular to said selected direction, and recording image data by charged particles emitted by said sample and storing said image data as a set of image data, each set of image data comprising a section of at least one of the marks; (d) repeating said removing step (b) and said scanning step (c) a plurality of times and generating a plurality of sets of image data; and, (e) analyzing said stored image data to identify a position of said section of said at least one of the marks in each set of image data and calculating a thickness of said slice from said position of said section of said at least one of the marks.