Scanning electron microscope

A scanning electron microscope in which a primary electron beam emitted from an electron source is scanned on a specimen and secondary electrons emitted from the specimen being detected to obtain a scan image, said scanning electron microscope comprising a primary electron current detector in the form of a groove for detecting a primary electron current, provided in the vicinity of a path of the primary electron beam, deflection means for deflecting the primary electron beam toward said primary electron current detector to cause the primary electron beam to pass along a surface of the detector, and means for identifying a current value of said primary electron beam with a maximum current value obtained by the primary electron current detector.

A scanning electron microscope in which a primary electron beam emitted from an electron source is scanned on a specimen and secondary electrons emitted from the specimen being detected to obtain a scan image, said scanning electron microscope comprising a primary electron current detector for detecting a primary electron current which is provided in the vicinity of a path of the primary electron beam, deflection means for deflecting the primary electron beam to the detector, a final aperture plate for the primary electron beam which is disposed on an electron source side of said deflection means, and a condenser lens for control of a beam current which is disposed on the electron source side thereof, wherein said condenser lens for control of the beam current is controlled with a focal point of said condenser lens positioned at said detector to cause the beam current to coincide with a preset value.

A method for detecting a primary electron beam current in a scanning electron microscope wherein a primary electron beam emitted from an electron source is scanned on a specimen, secondary electrons emitted from the specimen are detected to obtain a scan image, a primary electron current detector for detecting a primary electron current is provided in the vicinity of a path of the primary electron beam, deflection means for deflecting the primary electron beam is provided, a final aperture plate for the primary electron beam is disposed on an electron source side of said deflection means, and a condenser lens for control of a beam current is disposed on the electron source side thereof, said method comprising:

• a first step of deflecting said primary electron beam toward said primary electron current detector and identifying a deflection position at which an output current of said primary electron current detector indicates its maximum;
• and
• a second step of, under a condition that the primary electron beam is positioned at said deflection position, controlling said condenser lens for control of the beam current to cause the beam current to coincide with a preset value.

A scanning electron microscope in which a primary electron beam emitted from an electron source is scanned on a specimen and secondary electrons emitted from the specimen are detected to obtain a scan image, said scanning electron microscope comprising a primary electron current detector in the form of a groove for detecting a primary electron current, provided in the vicinity of a path of the primary electron beam, and deflection means for deflecting the primary electron beam into the detector, wherein said primary electron current detector is arranged along an inner wall of a beam path in the scanning electron microscope.

A scanning electron microscope in which a primary electron beam emitted from an electron source is scanned on a specimen and secondary electrons emitted from the specimen are detected to obtain a scan image, said scanning electron microscope comprising a deflector for deflecting the primary electron beam, and a primary electron current detector elongated in a direction substantially perpendicular to a deflection direction of said deflector, arranged in the vicinity of a path of said primary electron beam.