Patent ID: 7910898

Claim:
A method of measuring waveforms of beam currents, for receiving ion beam scanned in an X direction and measuring the waveforms of the beam currents flowing into a plurality of beam detectors by a beam monitor in which the plurality of beam detectors for receiving the ion beam and detecting the beam currents are arranged at constant intervals in the X direction, the method comprising: connecting the plurality of beam detectors to a single current measurement apparatus through respective switches; measuring the waveforms of the beam currents flowing into the current measurement apparatus by receiving the ion beam by the beam monitor, under a condition in which a plurality of switches skipped by “n” in the switches are simultaneously switched on, wherein the “n” is an integer of 0≦n≦(p−2) and satisfying Equation 1 or an equation mathematically equivalent to the Equation 1, the Equation 1 is Wb<{n·Wf+(n+1)Ws}, a width of a beam incident hole of each of the beam detectors in the X direction is Wf, a gap between the beam incident holes of adjacent beam detectors in the X direction is Ws, a beam width of the ion beam in the X direction is Wb, a total number of beam detectors is “p”; switching the switches, which are simultaneously switched on, under the condition; and repeating the steps of measuring and switching.