Ion Implantation and Synthesis of Materials - Studium

15 Ion Implantation in CMOS Technology:Machine ChallengesContributed by Aditya Agarwal 1 , Hans-Joachim Gossmann 1 , MichaelGraf, Thomas Parrill 2 , Leonard Rubin, and John Poate 3 (AxcelisTechnologies, Inc.)15.1 IntroductionThe history of ion implantation in semiconductors stretches back some 50 years.The first published report of the bombardment of semiconductor surfaces tochange electrical properties appears to be that of Ohl at Bell Laboratories in 1952(Ohl 1952). Shockley, at the same institution in 1954, filed a remarkably propheticpatent in which he detailed the doping possibilities of implanting donor oracceptor impurities to control the electrical properties (Shockley 1954). Thispatent basically describes the art as it is practiced today, including the annealing toremove damage and diffuse the dopant. There was much worldwide research inthe 1960s investigating the implantation phenomenon, but the technique was notwidely accepted into production until the 1970s. It was then that the value ofimplantation for threshold voltage adjustment and highly doped, self-alignedstructures contributed significantly to the integrated circuit (IC) revolution.The sophistication of implant machines and the devices they producehave evolved continuously over the past 50 years, and this chapter will give aflavor of the state-of-the-art of the technology and current challenges. At the sametime, the economic challenges or drivers cannot be overemphasized. Economicshave been an important factor in ion implantation from its inception in chipmanufacturing because the implanter cost was incremental to the diffusionsystems with which implant competed (McKenna 2000; Rose 1985).Silicon technology drives the modern world. A manifestation of its importanceis Moore’s Law, which describes the continuous shrinking of devices to improveperformance and cost. Tremendous investment is required to meet the demands of1Advanced Micro Devices, Inc.2Varian Semiconductor Equipment Associates3Colorado School of Mines213