Patent ID: 9502210
Filing Date: 2016-11-22
CPC Classification: H01J

Claim Text:
1. An ion implanter comprising: a beam deflector that deflects an ion beam incident through a previous stage beam path in a y direction by action of either or both of an electric field and a magnetic field and emits the beam to pass through a subsequent stage beam path extending in a z direction toward a wafer; a beam filter slit that is disposed on the subsequent stage beam path between the beam deflector and the wafer, partially shields the beam traveling through the subsequent stage beam path toward the wafer, and allows passage of a beam component toward the wafer, the beam component having a predetermined trajectory among beam components of the beam passing through the subsequent stage beam path; a dose cup that is disposed between the beam deflector and the beam filter slit and measures a part of the beam exiting from the beam deflector; and a trajectory limiting mechanism that is disposed between the beam deflector and the dose cup and prevents a first beam component having a first trajectory deviated from the predetermined trajectory, among beam components of the beam that exits from the beam deflector and is directed toward the dose cup, from being incident to a measurement region of the dose cup, wherein the trajectory limiting mechanism includes a first mask member comprising one or more first openings and a second mask member comprising one or more second openings, the first mask member and the second mask member are disposed to face each other in the z direction and prevent a second beam component having a second trajectory other than a third trajectory capable of passing through both the first openings and the second openings from being incident to the measurement region of the dose cup.