Ions are used in a plurality of semiconductor processes, such as implantation, amorphization, deposition and etching processes. These ions may be created within an ion source chamber and extracted through an extraction aperture in the ion source chamber.
There are several different types of ion implantation systems. A first type is referred to as a beam-line system. In a beam-line system, ions are extracted from an ion source, pass through a mass analyzer to select particular ions based on their mass to charge ratio, and are made into a parallel ribbon ion beam. Beam-line systems may also include deceleration stages, and other components to make the resulting ribbon ion beam more uniform.
A second type of ion implantation system is referred to as a plasma immersion ion implantation system. In these systems, the workpiece is disposed within the plasma chamber. Ions from the plasma are attracted toward the workpiece by negatively biasing the workpiece relative to the plasma.
A third type of ion implantation system uses a plasma chamber to create a plasma. Ions from that plasma are extracted through an extraction aperture and accelerated directly toward a workpiece, which is disposed outside the plasma chamber.
Each type of ion implantation has advantages and shortcomings. For example, the third type of system is relatively low cost and generates ion beams having high current, but lacks the capability to filter out unwanted species. It would be beneficial if there were an apparatus that retains the advantages of this third type of system, but was also able to filter unwanted species from the extracted ribbon ion beam.