A workpiece or semiconductor wafer is tilted as a ribbon beam is swept up and/or down the workpiece. In so doing, the implant angle or the angle of the ion beam relative to the workpiece remains substantially constant across the wafer. This allows devices to be formed substantially consistently on the wafer. Resolving plates move with the beam as the beam is scanned up and/or down. This allows desired ions to impinge on the wafer, but blocks undesirable contaminants.