Patent ID: 6897457
Filing Date: 2005-05-24
Classification: H01J

Abstract:
1. An ion implanter for implanting ions into a target substrate, comprising: an ion source; an ion beam extraction assembly for extracting ions from the ion source and forming a beam of extracted ions, the ion beam extraction assembly including therein a steering electrode having first and second electrically isolated electrode members defining therebetween a steering electrode aperture through which said ion beam may pass, and a voltage generator for applying a first voltage to said first electrode member and a second voltage to said second electrode member, the ion beam being controllably deflected in dependence upon the difference between said first and second voltages; said ion source comprising an arc chamber in which ions are formed, said arc chamber having a front face including an exit aperture through which ions can be extracted from the said arc chamber, said front face defining a first electrode, said steering electrode being adjacent the first electrode; a substrate holder downstream of the ion beam extraction assembly, for holding the target substrate; and a deflection monitor, arranged between the extraction assembly and the substrate holder, for monitoring the deflection of said ion beam, said monitor comprising: first and second electrically conductive surfaces, said first and second surface being adjacent and electrically isolated from one another, and defining an aperture therebetween to permit passage of at least a part of said ion beam in use; and a current monitor for measuring the difference between a current generated upon said first surface by a part of said ion beam and the current generated upon said second surface by another part of said ion beam, said current difference being indicative of the degree of deflection of said ion beam.