Mass analysis variable exit aperture

摘要

A method and apparatus is provided for reducing unwanted isotopes of an ion implantation species from an ion beamline. The apparatus herein disclosed is a mass analysis variable exit aperture that selectively reduces the size of an exit aperture as seen by an ion beam. In one embodiment, the variable mass analysis exit aperture is located within a mass analyzer at a position upstream of a resolving aperture and effectively limits the size of an exit aperture so as to allow passage of desired implantation isotope(s) while blocking the passage of unwanted implantation isotopes. In one particular embodiment, the mass analysis variable exit aperture has a mechanical drive mechanism that enables a blocking structure to be moved into the path of an ion beam in a graduated fashion as guided by a control unit that operates based upon one or more characteristics of the ion beam.