Method to correct first order astigmatism and first order distortion in multi-beam scanning electron microscopes

Abstract

An example multi-beam scanning electron microscope (MB-SEM) for correcting both astigmatism and linear distortion at least includes an electron source coupled to provide an electron beam, an aperture plate comprising an array of apertures, the aperture plate arranged to form an array of electron beamlets from the electron beam, and an electron column including a plurality of lenses and first and second stigmators, the electron column coupled to direct the array of electron beamlets toward a sample, wherein the first and second stigmators are arranged and excited to correct both astigmatism and linear distortion.