Abstract: This chapter provides an overview of electron beam processing. Particle beams, such as photon, electron, and ion beams, are frequently used in microfabrication for the production of integrated circuits (ICs) and for testing. Electron beams play an important role in submicrometer lithography, electron beam-assisted processes, such as deposition and annealing, and IC testing. This chapter reviews lithography and beam-assisted applications and discusses the nonconventional approaches to lithography, such as low-energy, high-energy, and multibeam lithographies and e-beam machine components, for example, cathodes, electro-optical components, and resists. The minimum electron energy used in beam processing is dictated by the physical and chemical reactions caused by electron interactions. These interactions range from target heating using the beam power to individual interactions causing primary scattering, secondary production, atomic excitation, and ionization. Chemical reactions, for instance, bond breaking, and polymerization initiated by the electron beam are important both in lithography and in general beam processing. The minimum electron energy that can produce the physical and chemical effects important in beam processing is approximately 5 eV and the maximum energy to minimize lateral scattering that limits the spatial resolution of e-beam patterning is several hundred kilo-electron volts.