Ion implantation method and ion implantation apparatus

An ion implantation apparatus that performs ion implantation into a substrate both by reciprocatively scanning an ion beam in a first direction and by mechanically driving the substrate in a second direction intersecting the first direction while making a driving speed of the substrate directly proportional to a beam current density of the ion beam in a region where the ion beam is incident on the substrate, the ion implantation apparatus comprising:

• a beam scanner that reciprocatively scans the ion beam in the first direction by an electric field or a magnetic field, a scanning speed of the ion beam within a surface of the substrate being variable;
• a substrate driver that mechanically drives the substrate in the second direction;
• a substrate position detector that detects a position of the substrate in the second direction and outputs position information representing the position;
• and
• a controller that performs control to form a circular implantation region and a peripheral implantation region surrounding it and a dose amount of which is different from that of the circular implantation region within a surface of the substrate by controlling the beam scanner based on the position information from the substrate position detector to thereby change a scanning speed distribution, in the first direction, of the ion beam within the surface of the substrate for each one-way scanning or each reciprocative scanning, according to the position of the substrate in the second direction, without a rotation of the substrate, and the scanning speed distribution includes a scanning speed distribution in which the scanning speed of the ion beam changes partially.