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Abstract

An electron beam inspection method and apparatus. The method includes controlling acceleration voltage of electron beam and electric field on a sample, beam current, beam diameter, image detection rate, image dimensions, precharge, discharge, or a combination of them, exposing an object to the electron beam, detecting in a sensor a physical change generated from the object, and inspecting or measuring the object on the basis of a signal representing the detected physical change. The apparatus includes an electron source (potential E2) for generating an electron beam, a deflector for scanning generated electrons, an objective lens for focusing the electron beam upon the object, a grid (potential E1) disposed between the object and the objective lens, a wafer holder (potential E0) for holding the object, a sensor for detecting generated secondary electrons, a potential controller for controlling the potential E0, E1 and E2, and a storage for storing optimum potential conditions. By changing conditions of an electron optic system such as potential E0, E1 and E2, the acceleration voltage and electric field on the object are controlled. For a material located at least in an upper layer of a plurality of materials forming the object, the secondary electron yield ratio can be made nearly unity and appropriate contrast of an obtained image can be provided with minimized influence of charge up.

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