Objective lens, electron beam system and method of inspecting defect

Abstract

An electron beam system or a method for manufacturing a device using the electron beam system in which an electron beam can be irradiated at a high current density and a ratio of transmittance of a secondary electron beam of an image projecting optical system can be improved and which can be compact in size. The surface of the sample S is divided into plural stripe regions which in turn are divided into rectangle-shaped main fields. The main field is further divided into plural square-shaped subfields. The irradiation with the electron beams and the formation of a two-dimensional image are repeated in a unit of the subfields. A magnetic gap formed by the inner and outer magnetic poles of the objective lens is formed on the side of the sample, and an outer side surface and an inner side surface of each of the inner magnetic pole and the outer magnetic pole, respectively, forming the magnetic gap have each part of a conical shape with a convex having an angle of 45° or greater with respect to the optical axis.

1 . An electron beam system comprising:
 an electron gun, an irradiating optical system, an electron beam-transmittable sample and an image-focusing optical system respectively disposed on one optical axis,   wherein a cross-over image formed by the electron gun is focused at a position adjacent to a principal plane of an objective lens in the image-focusing optical system, an image of an aperture for determining a subfield is focused on the sample, electrons passed through the sample is magnified by the objective lens to form an magnified image in front of a rear magnifying magnification lens, and an magnified image is formed on a detector by the magnifying magnification lens.   
   
   
       2 . An electron beam system comprising:
 an electron gun for emitting an primary electron beam;   a shaping aperture for shaping the primary electron beam to focus an image on a sample surface;   an electromagnetic deflector for separating electrons emitted from the sample from the primary electron beam after passing through an objective lens, and   a plural lenses for magnifying the electrons separation and focusing an image on a detector,   wherein a cross-over image to be formed by the electron gun is focused on a principal plane of the objective lens, and principal rays of a primary beam and a secondary beam pass through different positions in a distance between the electromagnetic deflector and the sample surface.