METHODS AND SYSTEMS FOR TRAPPING ION BEAM PARTICLES AND FOCUSING AN ION BEAM

摘要

A focusing particle trap system for ion implantation removes unwanted particles from an ion beam prior to implantation. An entrance electrode comprising an entrance aperture and is biased to a first base voltage. A center electrode is positioned a distance downstream from the entrance electrode and includes a center aperture. The center electrode is biased to a negative value, less than the first base voltage. An exit electrode is positioned a distance downstream from the center electrode and includes an exit aperture. The exit electrode is biased to a second base voltage. A first electrostatic field is generated from the entrance electrode toward the center electrode and a second electrostatic field is generated from the exit electrode toward the center electrode in order to trap unwanted particles within an ion beam.