Patent ID: 7982192

Claim:
A beam processing apparatus including a beam scanner having a two electrodes type deflection scanning electrode by opposed electrodes of a bilaterally-symmetric shape opposed to each other and having grooves extended in a beam line direction at opposed electrode faces thereof for carrying out deflection scanning of a periodically changing trajectory of a charged particle beam; wherein the beam scanner further includes shielding suppression electrode assemblies respectively at vicinities of upstream side and downstream side of the two electrodes type deflection scanning electrode and having openings in a rectangular shape for passing the charged particle beam; wherein each of the shielding suppression electrode assemblies is an assembly electrode comprising one sheet of a suppression electrode and two sheets of shielding ground electrodes interposing the suppression electrode; wherein a total of front side portions and rear side portions of the two electrodes type deflection scanning electrode is shielded by the two sheets of shielding ground electrodes; wherein a pair of electric field correcting electrodes extending in a direction orthogonal to an opposing direction of the two electrodes type deflection scanning electrode are arranged at a zone of the two electrodes type deflection scanning electrode and along the beam line direction to be opposed to each other by interposing a center axis of a place of reciprocally scanning the charged particle beam; wherein the pair of electric field correcting electrodes are the same as potentials of the upstream side suppression electrode and the downstream side suppression electrode, and wherein the pair of electric field correcting electrodes are arranged between the upstream side suppression electrode and the downstream side suppression electrode by penetrating the upstream side shielding ground electrode and the downstream side shielding round electrode which are close to the two electrodes type deflection scanning electrode, and the pair of electric field correcting electrodes are supported and connected conductively or insulatedly to vicinities of center portions of the upstream side suppression electrode and the downstream side suppression electrode.