Scanning electron microscope

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 the specimen, wherein said detector is capable of signal multiplication and the sensitivity is higher than the sensitivity of a collector electrode;
• at least one electrode disposed above a lowest pressure stage aperture, disposed nearest the specimen, wherein said electrode is at a positive potential with respect to said lowest pressure stage aperture and is adapted to deflect secondary electrons from the specimen to the detector;
• in which the lowest pressure stage aperture is adapted to shield an elevated pressure in the specimen chamber with respect to the remaining microscope column of the scanning electron microscope 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;
• and
• in which the pressure stage aperture and/or electrodes above it form one or more electrostatic lenses which are adapted for focusing the primary electron beam in an electric field between the pressure stage aperture and the electrodes above it or between the respective electrodes above it.

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;
• at least one pressure stage aperture disposed between the beam source and the specimen chamber, wherein each said aperture comprises an orifice through which a primary electron beam can be deflected onto a specimen within the specimen chamber, and at least one highly-sensitive detector having a bias potential with respect to the specimen, wherein said detector is capable of signal multiplication and the sensitivity is higher than the sensitivity of a collector electrode;
• in which said at least one pressure stage aperture has a top side and a bottom side and is comprised of layers of at least two conductive layers that are electrically insulated from one another and said aperture, wherein potentials can be applied to said conductive layers such that there is a potential difference between a top side and a bottom side of a respective pressure stage aperture;
• 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 of the scanning electron microscope and is farther 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;
• and
• in which the pressure stage aperture and/or electrodes above it form one or more electrostatic lenses which are adapted for focusing the primary electron beam in an electric field between the pressure stage aperture and the electrodes above it or between the respective electrodes above it.

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 though 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 the specimen, wherein said detector is capable of signal multiplication and the sensitivity is higher than the sensitivity of a collector electrode,
• at least one electrode disposed above a lowest pressure stage aperture, disposed nearest the specimen, wherein said electrode is at a positive potential with respect to said lowest pressure stage aperture and is adapted to deflect the secondary electrons from the specimen to the detector, and
• in which the lowest pressure stage aperture is adapted to shield an elevated pressure in the specimen chamber with respect to the remaining microscope column of the scanning electron microscope 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, and
• in which a combined electrostatic and magnetic lens is provided.

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 thc 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 wit respect to the remaining microscope column of the scanning electron microscope 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, and
• in which the secondary electrons pass through at least two pressure stage aperture orifices on their path to the detector, with a magnetic field prevailing in at least one of these orifices such that all magnetic field lines running through the lower pressure stage aperture also pass through the upper pressure stage aperture.

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 of the scanning electron microscope 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, and
• in which a counter-electrode is adapted to decelerate the secondary electrons and thereby support a transport of the secondary electrons to the detector.

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
• a magnetic lens focusing said primary electron beam, said magnetic lens having a specimen side pole shoe end, said specimen side pole shoe end having a cathode side and a specimen side, 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 of the scanning electron microscope and is farther adapted to allow secondary electrons from the specimen to pass though the orifice of the pressure stage aperture to contact said at least one detector, and
• in which said detector being disposed on said cathode side of said specimen side pole shoe end of said magnetic lens.