Self-sputtering phenomena in high-rate coaxial cylindrical magnetron sputtering

Abstract

In order to increase the deposition rate in magnetron sputtering, end plates were attached to both ends of cylindrical target. A current density of 0.1 A/cm2 was obtained with relatively low target voltage from 300 to 800 V. Deposition rates of Al and Cu were measured as functions of target voltage and current. From a discrepancy between measured and calculated values based on sputtering yield data, it is considered that sputtered Al atoms were ionized in a high density argon plasma and that the target was bombarded not only with argon ions but also with aluminum ions. Ionized Al atoms are estimated as about 18% of all the total ion current. Sputtering of Al and Cu in Kr and He were also examined. The same experiment was performed with another configuration of the electrode in which permanent magnet cores were placed inside the cylindrical target so that a spatially alternating magnetic field was applied along the axis. Discharge and sputtering characteristics were similar to the first one, although the shape of plasma and electron current to the substrate were much different.