Ion beam irradiation system and ion beam irradiation method

An ion beam irradiation system comprising an ion source, a mass analysis magnet, a mass analysis slit, a beam deflection scanner, a beam parallelizing device, and a wafer processing chamber, which are arranged in order so as to form a beam line, an ion beam extracted from a beam extraction electrode being transferred through the beam line and irradiated onto a wafer mounted on a platen, the beam deflection scanner scanning the wafer with the ion beam in a X direction that is a horizontal direction, the platen being moved in a Y direction that is a vertical direction with a wafer mechanical scan device installed in the wafer processing chamber, at least one of side cup current measurement device being arranged at an upstream side of the wafer to measure a beam current with the beam scan in the X direction, a beam current measurement device being arranged in the vicinity of an ion implantation position to the wafer in order to measure a beam current at the ion implantation position,

• the beam deflection scanner being controlled with a beam scan control calculation unit,
• the beam scan control calculation unit being configured so that a basic beam scan control function and a scan voltage correction function are changeable depending on the beam measurement result of the beam current measurement device, the basic beam scan control function and the scan voltage correction function being for controlling a beam scan speed in the beam deflection scanner with the scan voltage,
• the beam scan control calculation unit being configured so as to drive the wafer mechanical scan device with the mechanical scan speed corresponding to a set beam current, depending on the beam measurement result of the side cup current measurement device and so as to form multistage scan areas which are different in beam scan speed of the X direction and in beam scan width of the X direction, by setting more than one beam scan waveforms of the X direction which are different in beam scan speed while keeping a basic frequency set value in the beam scan control calculation unit with a constant, the more than one beam scan waveforms being set with generating scan voltage correction functions by correcting the scan voltages applied to the beam deflection scanner, and
• the beam scan control calculation unit being further configured so as to form a plurality of same dose amount areas by using a combination of different beam scan speeds in the X direction and different mechanical scan speeds in the Y direction.