Patent Number: 048662801
Section: abstract

An objective lens of an electron beam apparatus in which an electron beam emitted from an electron gun is converged onto a specimen, the reflected electron from the specimen or the secondary electron emitted therefrom is detected, and a fine pattern on the specimen is measured, comprises: a magnetic circuit consisting of an upper magnetic pole member having an opening adapted to transmit the electron beam to be converted which was emitted from the electron gun, a lower magnetic pole member provided so as to face the upper magnetic pole member, and a magnetic path member to connect the outer peripheral edges of the upper and lower magnetic pole members; a coil, provided for a part of the magnetic circuit, for generating the magnetic fluxes passing through the upper and lower magnetic pole members, the magnetic path member, and the space between the opening edge and the lower magnetic pole member when this coil is excited; and a moving apparatus which is disposed on the surface of the lower magnetic pole member opposite to the upper magnetic pole member and is movable on the plane perpendicular to the electron beam in the magnetic circuit in the state in which the specimen is put on the upper surface of the moving apparatus.