SCANNING ELECTRON MICROSCOPE FOR IRRADIATING SAMPLE WITH ELECTRON BEAMS HAVING SMALL ENERGY WIDTH

PROBLEM TO BE SOLVED: To provide a scanning electron microscope equipped with a correction device for forming electron beams having dispersed energy and low spherical aberration.SOLUTION: Electron rays emitted from an electron gun 8 are made incident to a prism aberration correction device 4 via a current value controlling aperture 3 so as to remove geometric aberration generated by a prism 5. Thereafter, the electron rays pass through the prism 5 so that the energy thereof is dispersed, and the degree of dispersion is further amplified by a dispersion angle amplifier 6. Then, the electron rays pass through a condenser lens 9, a beam diameter controlling aperture 10, a spherical aberration correction device 11 and an objective lens 1 to be focused on an observation sample 2.