AVS 45th International Symposium
    Vacuum Metallurgy Division Monday Sessions
       Session VM+TF-MoM

Paper VM+TF-MoM4
Characterization of Magnetron-Sputtered Partially Ionized Deposition as a Function of Metal and Gas Species

Monday, November 2, 1998, 9:20 am, Room 328

Session: Ionized-PVD: Processes, Properties, and Applications
Presenter: M.M.C. Allain, University of Illinois, Urbana-Champaign
Authors: M.M.C. Allain, University of Illinois, Urbana-Champaign
D.B. Hayden, University of Illinois, Urbana-Champaign
D.R. Juliano, University of Illinois, Urbana-Champaign
D.N. Ruzic, University of Illinois, Urbana-Champaign
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A dc planar magnetron with a 33-cm diameter target is coupled with a secondary plasma source to ionize the sputtered metal neutral flux to control the angular distribution of the flux arriving at the surface of the substrate. The secondary radio-frequency (rf) plasma is created between the sputtering target and the substrate by a multi-turn coil located in the vacuum chamber. The rf plasma increases the electron density, which results in significant ionization of the neutral metal flux from the sputtering target. By applying a small negative bias to the substrate, metal ions are drawn to the substrate at normal incidence. A gridded energy analyzer and a quartz crystal microbalance (QCM) are attached to a pulley system that allows the ion and neutral deposition rates to be determined along the substrate plane. The ionization fraction of the flux incident onto the QCM can then be determined as a function of position. The ionization rate is a sensitive function of the metal's ionization potential (IP). The electron energy distribution in the plasma is affected by the metal being sputtered and the working gases' ionization and excitation potentials (EP). While keeping the magnetron power, rf coil power, target to substrate distance and pressure constant, the ionization fraction, as a function of position, has been measured. The electron temperature and density are measured using a Langmuir probe. The target metals analyzed in design of this experiment are aluminum(IP=5.98eV), copper(IP=7.72eV), and titanium(IP=6.82eV). The working gases will be krypton(IP=13.99eV, EP=1.702eV), argon(IP=15.76eV, EP=2.55eV), neon(IP=21.56eV, EP=3.52eV), and helium(IP=24.58eV, EP=5.36eV). An analytic model is compared to the experimental results.