Feasibility study of a multiple beam SEM for a defect inspection

We have developed an electron beam inspection system based on projection electron microscopy(1). SE image is magnified by the projection optics and then detected by a CCD detector. For this method very large numbers of pixel data can be obtained at once, however because of large beam current this method have a fear of a surface charging. We started to study a new multiple beam SEM using image projection type SE detection. For this type SEM, a primary optics is more important than the secondary one, and then we start to study only the primary optics.