Patent ID: 7550724
Filing Date: 2009-06-23
Classification: H01J

Abstract:
1. An electron beam device comprising: an electron gun having an electron source for generating a primary electron beam; a differential exhaust diaphragm for providing communication between an electron gun section having said electron gun accommodated therein and a mirror section having a specimen accommodated therein; and a condenser lens for temporarily converging said primary electron beam on an aperture of said differential exhaust diaphragm or in the vicinity thereof, said electron beam device further comprising: a diaphragm mechanism disposed in an optical path from said electron source to said condenser lens for switching between aperture diameters; and a changeover mechanism for switching between the aperture diameters of said diaphragm mechanism according to a position of a crossover point to which said primary electron beam from said condenser lens is temporarily converged by said condenser lens.