Patrick Morse, Arizona Thin Film Research LLC, Tucson, AZ
Traditional uniformity modeling in large-area magnetron sputtering often relies on static magnetic field approximations, frequently overlooking the dynamic influence of the Lorentz force and space-charge effects on ion-target interactions. Building upon previous work that identified significant plasma asymmetries in rotary cathode pairs, this study utilizes GPU-accelerated solvers in COMSOL Multiphysics® to extend the simulation domain from the plasma sheath to the substrate surface.
By implementing the latest Direct Sparse Solvers (cuDSS), we present a high-fidelity, multi-species model that tracks the ballistic and diffusive transport of sputtered atoms through a background of neutral Argon. This approach allows for the high-throughput calculation of over 105 particles, providing statistically significant data on the Angle of Incidence (AOI) and Arriving Energy (Ei) distributions across the substrate.
Results demonstrate that the electric field asymmetries previously observed in the plasma density leads to non-uniform energy flux and distributions, even when the integrated thickness uniformity remains within industry-standard tolerances. We explore how these variations in arrival kinetics correlate with localized changes in film density and intrinsic stress. This work highlights the "Digital Revolution" in surface engineering, where GPU-enabled computational speed allows for the optimization of complex cathode geometries to ensure not just thickness uniformity, but film homogeneity.