Concepts and designs of ion implantation equipment for semiconductor processing

Manufacturing ion implantation equipment for doping semiconductors has grown into a two billion dollar business. The accelerators developed for nuclear physics research and isotope separation provided the technology from which ion implanters have been developed but the unique requirements of the semiconductor industry defined the evolution of the architecture of these small accelerators. Key elements will be described including ion generation and beam transport systems as well as the techniques used to achieve uniform doping over large wafers. The wafers are processed one at a time or in batches and are moved in and out of the vacuum by automated handling systems. The productivity of an implanter is of economic importance and there is continuing need to increase the usable beam current especially at low energies.