Electrostatic scanning of MeV ion beams

High energy implanters for 300 mm substrates are required to operate over a large range of energy and beam current. This must be accomplished without compromising throughput or the advantages of serial implant architecture, such as beam parallelism, high tilt angles, and low mechanical wafer stress. Modern ion implanters employing electrostatic scanning of the ion beam have typically limited the beam energies to the range of 250 keV. Applying this technology to scanning of 1.6 MeV beams for 300 mm applications requires significant adaptation in order to maintain high beam transmission for low energy beams as well. This is accomplished through the use of variable scan plate spacing and length. The details of scanner operation over a wide dynamic range of beam energy and space charge is presented.