Patent ID: 7935945

Claim:
An ion implantation method of implanting ions into a substrate using both a ribbon-like ion beam in which, with or without performing an X direction sweep, a dimension in an X direction is larger than a dimension in a Y direction that is orthogonal to the X direction, and a mechanical scan of the substrate in a direction intersecting with a principal face of the ion beam, said method comprising: a scan speed calculating step of setting an initial value of a scan number of the substrate to 1, and calculating a scan speed of the substrate by using a beam current of the ion beam, a dose amount to the substrate and the initial value of a scan number of the substrate; a scan speed determining step of: determining whether the scan speed of the substrate is within a predetermined allowable scan speed range or not; if the scan speed is within the allowable scan speed range, setting the current scan number and the current scan speed as a practical scan number and a practical scan speed, respectively; if the scan speed is higher than an upper limit of the allowable scan speed range, aborting a process of obtaining the practical scan number and the practical scan speed; and, if the scan speed is lower than a lower limit of the allowable scan speed range, incrementing the scan number by one to calculate a corrected scan number; a corrected-scan speed calculating step of, when the corrected scan number is calculated, calculating a corrected scan speed by using the corrected scan number, the beam current, and the dose amount; a repeating step of, when the corrected scan speed is calculated, performing a process of said scan speed determining step on the corrected scan speed, and repeating said scan speed determining step and said corrected-scan speed calculating step until the corrected scan speed is within the allowable scan speed range; and an ion implanting step of implanting ions into the substrate in accordance with the practical scan number and the practical scan speed.