Patent ID: 7683348

Claim:
For use with a semiconductor processing tool having an evacuated region for treating a workpiece by directing an ion beam to strike a workpiece, apparatus comprising: a source, beam transfer structure and a workpiece support defining a path of travel for ions in an ion beam that impinge on one or more workpieces at an implantation station, a sensor comprising an electrically conductive base having a generally planar strike plate and an electrically conductive mask in electrical contact with the base that comprises a mask body having an array of elongated throughpassages that extend from a front surface of the mask body, through the mask body to a rear surface of the mask body in contact with the generally planar strike plate of the base for dividing an ion intercepting cross section of said beam into regions, and a housing that supports the sensor while holding the rear surface of the mask body in engagement with the generally planar strike plate of the conductive base, said mask throughpassages including walls extending through the mask body to allow ions to pass through the mask body and strike said conductive base while impeding ions reaching the sensor from rebounding into the evacuated region of the processing tool.