Ion implantation apparatus

An ion implantation apparatus comprising:

• a rotating body that rotates in a fixed direction,
• a vacuum chamber that houses the rotating body, and
• an ion beam injecting portion that injects an ion beam to a wafer placed on the rotating body,
• wherein the rotating body comprises one or two or more wafer placement boards having a wafer placement face on one face,
• a gas discharge path for the purpose of discharging gas present on the wafer placement face to a face opposite to the wafer placement face,
• a gas evacuation member provided protruding from one face of the wafer placement board, having a first gas evacuation wall face, and
• a driving portion that rotates the wafer placement board,
• wherein the gas evacuation member is disposed behind the gas discharge path in the direction of rotation, the first wall face of the gas evacuation member is a frontal face in the direction of rotation, and is a curved face or a flat face rising up from the one face having an angle of elevation greater than 0 degrees and less than 90 degrees when a plane parallel to the wafer placement face is used as a level plane, and
• functions such that gas is discharged from the gas discharge path to the face opposite to the one face of the wafer placement board by the first wall face colliding with gas present on one face of the wafer placement board due to rotation of the wafer placement board.