Patent ID: 6933507
Filing Date: 2005-08-23
Classification: H01J

Abstract:
1. An apparatus for variable focusing of charged particles used for implanting a plurality of charged particles into semiconductor materials thereby modifying properties of said semiconductor materials said apparatus comprising: a structure manufactured from a magnetic material said structure having a long dimension and a short dimension; an upper magnetic core member having said long dimension between its ends; a lower magnetic core member having said long dimension between its ends said lower core member being oriented with its axis substantially parallel to the axis of said upper core and its ends substantially aligned with the ends of said upper core member; a plurality of coil units distributed along both said upper and lower core members each said coil unit comprising a single continuous electrical circuit that surrounds an individual core member; additional magnetic members connected between ends of said upper and lower magnetic core members to form the short dimensions of a rectangular frame; a plurality of coil units distributed along both additional magnetic members forming the short dimensions of said rectangular frame; and means for independently exciting said upper and lower coil units by currents which are in one direction for the coil units distributed along said upper magnetic core member and in the opposite direction for the coil units distributed along said lower magnetic core member when viewed from one end of said rectangular frame; and means for independently exciting said coil units distributed along one or both additional magnetic members.