Process simulation of industrial vacuum arc deposition

Abstract

Vacuum deposition and especially vacuum arc deposition represent efficient methods to produce protective or decorative coatings and are now widely used for industrial applications. An advantage consists in the nearly collision-free propagat ion allowing high energies of the film forming particles. However, the straight expansion of the energetic plasma means that a homogeneous deposition of three-dimensional parts is only possible by the relative movement of plasma source and substrates, usually managed by rotations of the substrate holders. Hence, the deposition conditions vary periodically leading to a more or less pronounced (nano)layered film structure. The simulation program SimCoat aims to support the structural and technological optimization of the deposition process in industrial vacuum arc coaters. It is based on the kinematics of substrate and plasma source movements and on simplified but experimentally supported modeling of the film growth, carefully considering the real geometrical conditions. Besides others the output parameters include film thickness and film structure (composition, density variations) in dependence e.g. on the geometry of the parts, on their position inside the chamber or on the kind of batch. The program system SimCoat has a modular structure, which allows the stepwise implementation of additional features. Input and output windows are adapted on the demands of engineers. Apart from recording the numerical data, the process and its results can be visualized to get direct insight into the interrelations between process parameters and film properties. The potential of SimCoat is demonstrated for the deposition of tetrahedral bonded carbon films by the laser controlled pulsed vacuum arc technique (Laser-Arc) in a large volume industrial coater. Vacuum arc technology is distinguished by the high degree of ionization and the high kinetic energy of the film forming particles, which allow the deposition of very hard films from conventional titanium nitride up to tetrahedral bonded carbon