BEAM PROCESSING APPARATUS

摘要

A beam processing apparatus is provided to enhance accuracy of parallel beam after ion beam scanning by maintaining constantly a diameter of ion beams irrespective of positions in a scanning area. A beam processing apparatus includes beam scanners(36A,36B) which perform deflection scanning that periodically varies orbits of charged particle beams using two polar type deflection scanning electrodes. The beam scanners include shield preventing electrode assemblies. The shield preventing electrode assemblies having a square shape aperture for penetrating the charged particle beams are disposed around upper and lower portions of the two polar type deflection scanning electrodes. Each of the shield preventing electrode assemblies includes one suppress electrode and two shield ground electrodes, which are formed at both sides of the suppress electrode. Forward and backward portions of the two polar type deflection scanning electrodes are shielded by the two shield ground electrodes.