Patent ID: 6590210
Filing Date: 2003-07-08
Classification: H01J

Abstract:
A scanning electron microscope having a microscope column and an optical axis, wherein said column comprises:a beam source capable of producing a primary electron beam; a specimen chamber; one or more pressure stage apertures disposed between the beam source and the specimen chamber, wherein each said aperture comprises an orifice through which the primary electron beam can be deflected onto a specimen within the specimen chamber; at least one highly-sensitive detector having a bias potential with respect to a specimen, wherein said detector is capable of signal multiplication and the sensitivity is higher than the sensitivity of a collector electrode; and in which a lowest pressure stage aperture, disposed nearest the specimen, is adapted to shield an elevated pressure in the specimen chamber with respect to the remaining microscope column and is further adapted to allow secondary electrons from the specimen to pass through the orifice of the pressure stage aperture to contact said at least one detector.