Scanning electron microscope

A scanning electron microscope comprising:

• an electron source;
• an image shifting deflector system including a first deflector and a second deflector to shift an irradiation position of a primary electron beam emitted by the electron source on a specimen;
• and an objective lens that focuses the primary electron beam using a magnetic field leaked from a lens gap of the objective lens;
• and
• a retarding electric field creating means that creates a retarding electric field for retarding the primary electron beam is disposed between the specimen and the objective lens, the lens gap of the objective lens opens toward the specimen, and the first deflector disposed closer to the specimen than the second deflector and interposed between the objective lens and the specimen, wherein the retarding electric field creating means deflects the primary electron beam using an electrostatic field to offset a deflection caused by a leaked magnetic field.

A scanning electron microscope comprising:

• an electron source;
• an objective lens that focuses the primary electron beam emitted from the electron source;
• a scanning deflector means that includes a first deflector and a second deflector to shift the primary electron beam to scan the specimen with the primary electron beam;
• an image shifting deflector means that shifts a center of scanning;
• a secondary signal detector that detects a secondary signal produced by the specimen when irradiated with the primary electron beam;
• and a height measuring means that measures the height of the specimen by using a laser beam;
• wherein:
• the objective lens has a lens gap opening toward the specimen;
• and
• the first deflector, disposed closer to the specimen than the second deflector, forms a deflecting electric field in a region corresponding to an effective principle plane of the objective lens;
• and
• wherein the first deflector is an octupole deflector including a plurality of conductor plates, a primary electron beam passing aperture, and insulating slits extending radially from the primary electron beam aperture, and
• the laser beam travels through insulating slits formed between the conductor plates.

A scanning electron microscope comprising:

• an electron source;
• an image shifting deflector system including a first deflector and a second deflector to shift an irradiation position of a primary electron beam emitted by the electron source on a specimen;
• and a magnetic objective lens and an electrostatic lens that focus the primary electron beam;
• wherein the magnetic objective lens has a first magnetic pole and a second magnetic pole, an opening formed in the first magnetic pole is greater than an opening formed in the second magnetic pole, the first deflector, disposed closer to the specimen than the second deflector and interposed between the objective lens and the specimen, deflects the primary electron beam using an electrostatic field to offset a deflection caused by the magnetic lens.

A scanning electron microscope comprising:

• an electron source;
• an image shifting deflector system including an upper deflector and a lower deflector to shift an irradiation position of a primary electron beam emitted by the electron source on a specimen,
• an objective lens that focuses the primary electron beam;
• a setting means for setting a position to which the image shifting deflector system shifts an image;
• and
• a setting nullifying means that, responsive to a position set by the setting means being in a specific region including a center of a deflection range for the image shifting deflector system, nullifies the position set by the setting means or provides a warning.