High-rate sputtering with a torus plasmatron

High-rate sputter sources for cylindrically symmetric arrays of target and substrate can be put into being by using the principle of ring gap discharges. Electrostatic and magnetic focusing of a gas discharge allows generation of a toroidal plasma of high density on either the inner or outer surface of a tubular target. Against cylindrically symmetric diode arrays with homogeneous discharge, such a setup is characterized by an increase in sputter rates of about one order of magnitude. Such high rates may also be attained with substrate arrangements extending toward the cylinder axis by joining several toroidal discharges one after the other. With copper and sputtering toward the outside, for instance, the deposition rates exceed 1 μm/min (tube distance about 50 mm). Depending on the selected array, sputtering toward the inside gives deposition rates that are several times as high. Further advantages of Torus Plasmatron Sputter Sources are low working pressure, low specific energy demand, high degree of material utilization, and almost universal coating possibilities, i.e., also of profiles. 8 figures