Patent attributes
Provided herein are approaches for reducing particles in an ion implanter. An electrostatic filter may include a housing and a plurality of conductive beam optics within the housing. The conductive beam optics are arranged around an ion beam-line directed towards a wafer, and may include entrance aperture electrodes proximate an entrance aperture of the housing. The conductive beam optics may further include energetic electrodes downstream along the ion beam-line from the entrance aperture electrodes, and ground electrodes downstream from the energetic electrodes. The energetic electrodes are positioned farther away from the ion beam-line than the entrance electrodes and the ground electrodes, thus causing the energetic electrodes to be physically blocked from impact by an envelope of back-sputter material returning from the wafer. The electrostatic filter may further include an electrical system for independently delivering a voltage and a current to each of the conductive beam optics.
