| 摘要 |
<p>A system (10) for scanning semiconductor wafers through an ion beam (14A). Ion beam line (14) generates an ion beam oriented in a prearranged direction. A scan wheel (15) carries a plurality of semiconductor wafers and a drive arrangement (22, 23) rotates the scan wheel about its central axis to scan the wafers across the ion beam in one coordinate direction. A scan arrangement (18, 19) produces relative scanning movement between the scan wheel and the ion beam in another coordinate direction. The scan wheel assembly (15) comprises a central hub (32), a plurality of separate spoke arms (31) mounted to the hub, and a plurality of heat sink elements (15A) formed on the outer ends of the spoke arms for mounting a semiconductor wafer thereon. The scan arrangement (18, 19) overscans the heat sink elements in and out of the ion beam so that the ion beam strikes only a portion of the spoke arms in one overscan position and the total heat load produced on the scan wheel assembly by the ion beam is susbstantially reduced. Temporary wafer clamps (49) and restraints (48) hold the wafer (80) on the heat sink until centrifugal force due to wheel spinning is sufficient to press the wafer on the heat sink. Congruent triangle mounting and drive arrangements for the scan wheel provide the l/r velocity function for slow scan to achieve implant uniformity. <IMAGE> <IMAGE> <IMAGE></p> |
