Patent ID: 8053726
Filing Date: 2011-11-08
Classification: G01N,H01J,H01L

Abstract:
1. An inspection apparatus comprising: a beam source for irradiating primary charged particles against a sample to be inspected; a retarding-field type objective lens for decelerating said primary charged particles as well as for accelerating secondary charged particles generated by said electron beam irradiated against said sample to be inspected; a detector for detecting said secondary charged particles; an E×B deflecting system for deflecting said secondary charged particles toward said detector by a field where an electric field and a magnetic field cross at right angles; and an electrode for controlling the electric field intensity in a plane of said sample to be inspected, said plane being exposed to the irradiation of said primary charged particle, said electrode being arranged between said retarding-field type objective lens and said sample to be inspected and having a shape approximately symmetrical with respect to the optical axis of irradiation of said primary charged particles, wherein said secondary charged particles are projected by a projecting method so as to form an image of said sample to be detected by said detector, wherein said inspection apparatus includes a numerical aperture and a field aperture, said numerical aperture constructing a telecentric electronic optical system with said retarding-field type objective lens, said electron beam apparatus further comprising means for measuring the amount of the electric charge of said electrode and applying voltage to the electrode to irradiate electrons corresponding to the measured amount of the electric charge to offset the electric charge on the electrode.