Scanning electron microscope

Claim 1

A scanning electron microscope in which secondary electrons from the specimen surface are detected and in which the topography of the specimen does not produce undesired contrasts comprising: a means for focusing an electron beam onto a specimen including an objective lens; a means for scanning a desired region on the specimen with the electron beam; a stage assembly for tilting, translating, or rotating the specimen; a first and a second detector for detecting secondary electrons emanating from the specimen in response to the incidence of the electron beam, the detector being disposed both on the same side of the objective lens nearest the stage assembly and each on opposite sides of the optical axis of the electron beam, the first detector being disposed relatively close to the optical axis of the beam, the second detector being disposed relatively remotely from the optical axis such that the stage assembly does not collide with the secondary detector when the stage assembly is tilted through its normal range of motion; a first and a second amplifier for amplifying the output signals from the first and second detectors, respectively, the amplifiers each having means for adjusting the gain for compensating for the imbalance between the intensities of the output signals from the detectors such that the undesired contrasts caused by specimen topography are reduced; an arithmetic circuit that arithmetically processes the output signals from the amplifiers; and a cathode-ray tube to which the output signal from the arithmetic circuit is supplied as an intensity-modulating signal.