ION-IMPLANTATION FOR SILICON DEVICE MANUFACTURING - A VACUUM PERSPECTIVE

Ion implantation systems rely on a diverse vacuum environment to accom plish the goals of doping of Si materials for formation of electronic devices. Failure to manage the gas hows and contaminants in this compl ex vacuum system can lead to severe penalties for integrated circuit p rocessing. Examples of vacuum control issues in ion sources, beam tran sport, dosimetry, wafer charging, and contamination are discussed. Con tamination issues involve a mix of ion and vapor transport of dopants and metals, charge exchange and molecular breakup collisions, and part icle generation associated with electrode arcing. Additional factors i n good vacuum design include operation of contamination-free, rapid-cy cle loadlocks and safety issues, such as management of potentially exp losive gas mixtures during regeneration of cryopumps. (C) 1996 America n Vacuum Society.