Patent ID: 7994486

Claim:
A substrate scanner apparatus for scanning a substrate through an ion beam in an ion implanter, the substrate scanner apparatus comprising: a base which defines first and second paths; a substrate carriage positioned to move along said first path, the substrate carriage being coupled to a substrate holder such that the substrate holder, and any substrate held by the substrate holder, moves with the substrate carriage; a reaction mass carriage positioned to move along said second path provided by the base; means for controlling movement of the substrate carriage and the reaction mass carriage such that movement of the substrate carriage along said first path causes a corresponding movement of the reaction mass carriage along said second path in a reverse direction to movement direction of said substrate carriage, thereby counteracting reaction forces generated by movement of the substrate carriage, a first moving force-generation unit for providing a movement-generating force between either the substrate carriage and the base or the reaction mass carriage and the base, and wherein the means for controlling movement controls movement of the carriage provided with the movement-generating force, and the means for controlling movement comprises a physical link between the substrate carriage and the reaction mass carriage for providing a corresponding movement of the other of the substrate carriage and the reaction mass carriage in the reverse direction.