3D modeling of sputter and reflow processes for interconnect metals

We report full 3D Monte Carlo (MC) and molecular dynamics (MD) simulations of aluminum sputtering and reflow. The topography evolution and surface diffusion during deposition are simulated with a mesoscopic hard-sphere MC model, where each sphere represents a cluster of material (/spl sim/100 /spl Aring/ in diameter). We have developed appropriate scaling laws, which allow the interaction between the spheres to be deduced from microscopic MD calculations. The results of the simulations reflect key experimental observations like absence of adhesion to the substrate after reflow, and the temperature dependence of via fill during high temperature sputter deposition.