ELECTRON DETECTOR

摘要

Secondary electrons emitted by a body under electron beam bombardment into the magnetic field of a magnetic electron lens in which the body is placed are constrained and directed by the magnetic field so that the lens either focusses them to a small region at the centre of a hemispherical collector assembly so that the direction of the electrons do not affect their angle of incidence on the collector, or brings their paths to be within a small angle (5 DEG ) of the axis of the lens so that they impinge on a plane collector substantially normally. The invention is of particular value in the electron beam inspection of an integrated circuit when operating.