Patent ID: 7385197

Claim:
An electron beam apparatus comprising: an electron irradiation optics for irradiating a plurality of primary electron beams onto a sample surface; a scanning deflector for performing a scanning operation with said plurality of primary electron beams across the sample surface; a beam separator for separating secondary electron beams emanating from respective scanned regions on the sample from said primary electron beam; a magnifying electron lens for magnifying a distance between any two beams of the plurality of secondary electron beams that have been separated by said beam separator; an optical output converter for converting the plurality of magnified secondary electron beams to optical signals; a photoelectric conversion device for converting said optical signal to an electric signal; an optical magnifying lens for magnifying said optical signal from said optical output converter into an image on said photoelectric conversion device; and a multi-aperture plate disposed in front of said photoelectric conversion device and having a plurality of apertures formed therethrough, said aperture having an aperture area that is large in a peripheral region.