*P. McCarthy, T. Sgrilli, V. Bellido-Gonzalez, R. Brown, A. Azzopardi, P. Killen, B. Daniel, D. Monaghan, Gencoa Ltd, Liverpool, United Kingdom
The various possibilities of optimising the control over plasma processes have attracted the attention of many R&D projects in the field. The upgrade of magnetron sputtering processes from development to large-scale and large-area production needs to rely both on the cathode and the anode design for any given plasma discharge. A well-defined anode throughout a process is key for its stability and reproducibility, as well as for obtaining coatings with specific properties. While this is ordinarily achieved in planar magnetrons, rotatable cathodes present more challenges. One way to ensure a stable anode able to collect most of the electron current is via a magnetic guidance, to ensure that elecrons have a preferential pathway. For this to occur, a magnetic guide needs to be engineered, taking into account its interaction with the cathodes magnetic field. In this paper some implications and benefits of such a control over the plasma discharge are shown. The operation of a magnetic guide in rotatable cathode systems, combined with the use of diverse and complex power configurations, allows the control of the sample exposure to electron and ion bombardment, which have direct consequences on the film properties, including hardness, density, stress, heat load as well as coating uniformity. Relevant examples will be presented.