Patent ID: 6177679
Filing Date: 2001-01-23
Classification: H01J

Abstract:
An ion implanter comprising:an ion source for producing an ion beam which travels along an ion beam path in the implanter for implantation into a wafer;an accelerator, disposed downstream from said ion source along said ion beam path, for accelerating the ion beam, said accelerator having an inlet portion through which the ion beam enters and an outlet portion through which the ion beam exits; andmeans for removing from the ion beam undesired impurity ions traveling along the same path as impurity ions desired for implantation and whose product of mass and energy is the same as that of the desired impurity ions but whose energy level is different than that of the desired impurity ions, said means for removing comprising an interceptor plate disposed in said ion beam path downstream of the inlet portion of the accelerator, and a high voltage power supply electrically connected to said interceptor plate so as to impress a voltage thereacross, whereby undesired impurity ions of an energy level lower than that of said voltage are removed from the ion beam by the interceptor plate.