Patent ID: 8604443

Claim:
A system for controlling rotation of a ribbon beam in an ion implanter, comprising: a detector for measuring a beam profile of the ribbon beam, the ribbon beam comprising a principal axis defined by a centroid of the ribbon beam in a direction of travel of the ribbon beam and a planar axis perpendicular to the principal axis; a controller for receiving beam profile information from the detector and for sending control signals to control first and second output currents; and a quadrupole lens comprising: an upper member having a first and a second coil that are generally disposed in respective first and second regions of the upper member and are configured to conduct, independently of one another, a first and a second current, respectively; and a lower member having a third and a fourth coil that are generally disposed in respective third and fourth regions opposite to respective first and second coils of the upper member and are configured to conduct, independently of one another, a third and a fourth current, respectively; and a lens gap defined between the upper and lower members configured to transmit the ribbon beam, such that the first through fourth currents produce a 45 degree quadrupole field to exert a rotational force on the ribbon beam about its principal axis.