Patent ID: 6919577

Claim:
An electron beam apparatus, comprising: a table which mounts a specimen and is movable in three dimensional directions; an electron beam optical system including an electron beam source, an element for deflecting an electron beam emitted from the electron beam source, an objective lens for converging and irradiating the electron beam deflected by the deflection element onto a specimen, and a detector for detecting a secondary electron emanated from the specimen by the irradiation of the electron beam; a surface height detection system for detecting height of the surface of the specimen mounted on the table which includes a projection optical unit obliquely projecting a light onto a surface of the specimen, a detection optical unit for detecting light reflected from the surface of the specimen by the projection of the light, and a signal processing unit for calculating a height of the surface of the specimen by using signal outputted from the detection optical system; a focus control system for controlling a relative position between a focus position of the electron beam optical system and the table in accordance with information of the height from the surface height detection unit; and an image processing system which obtains an image from the detected secondary electron and processes the obtained image to detect a defect on the surface of the specimen.