Patent ID: 7365325

Claim:
A method of observing a specimen, comprising the steps of: irradiating and scanning a convergent electron beam, from an oblique direction, on surface of a calibration substrate on which a pattern with a known shape is formed, and thereby obtaining a beam tilt SEM image of the pattern formed on the calibration substrate; calculating an angle of the oblique direction of the electron beam irradiated on the surface of the calibration substrate by use of the information about a distortion of the beam tilt SEM image of the pattern estimated from a geometric deformation of the beam tilt SEM image of the pattern; adjusting the angle of the oblique direction of the electron beam to a desired angle by using information of the calculated angle; irradiating the electron beam from the adjusted desired angle on a specimen substrate on which a pattern is formed, and thereby obtaining a beam tilt SEM image of the pattern formed on the specimen substrate; and processing the beam tilt SEM image of the pattern formed on the specimen substrate by use of the information of the desired angle, and thereby, in combination with information of another SEM image of the pattern formed on the specimen substrate, obtaining a 3D image of the pattern formed on the specimen substrate or a shape of a cross section of the pattern formed on the specimen substrate.