Patent ID: 6333510
Filing Date: 2001-12-25
Classification: B82Y,H01J

Abstract:
An electron beam apparatus, comprising:an electron optical system including an electron beam source, an element for deflecting electron beams emitted from the electron beam source, an objective lens for converting and irradiating electron beams deflected by the deflection element onto a specimen and a detector for detecting a secondary electron emanated from the specimen by irradiation of the electron beams;a projection optical system for projecting a light pattern onto a surface of the specimen in the vicinity of a beam axis of the electron optical system from an oblique direction to the surface;a detection optical system for detecting an image of the light pattern projected onto the surface of the specimen and outputting information of a position of the image of the light pattern;a surface height detection unit for outputting height information of the surface of the specimen by using the output information from the detection optical system; anda focus controller for focusing the electron beam onto the surface of the specimen by controlling the objective lens of the electron optical system in accordance with the height information from the surface height detection unit.