Patent ID: 6335530
Filing Date: 2002-01-01
Classification: H01J

Abstract:
An objective lens for a scanning microscope disposed between a sample and a charged particle beam source for focusing a charred particle beam produced by the charged particle beam source, comprising: an inner magnetic pole piece at least a bottom portion thereof facing the sample having a conical outer surface the entirety of which extends along an axis disposed at an angle of 30Â° or less with respect to an optical axis of the lens, the conical outer surface portion of the inner magnetic pole piece comprising a sector of an imaginary cone tapering outward in a direction opposite the sample to extend rearward of the conical outer surface portion; an outer magnetic pole piece disposed substantially entirely inside the surface of the imaginary cone rearward of the conical outer surface portion of the inner magnetic pole piece; and an exciting coil disposed inside the surface of the imaginary cone rearward of the conical outer surface portion of the inner magnetic pole piece for exciting the inner and outer magnetic pole pieces.