Abstract: Solid-liquid two-phase micro flow in multilevel rough gap between the grooved pad and wafer is taken as a study object. Lattice Boltzmann method (LBM) is used to analyze the slurry flow in the multilevel rough gap combining with the computer generation technology of rough surface, and then, the trajectories of the solid particles in the slurry are simulated. The feasibility of this new approach, which offers detailed images of flow in planarization process and trajectories of particles, is demonstrated. The motion and collision of solid particles in the multilevel rough gap are studied preliminarily. The results show that this new approach, a combination of the computer generation of multilevel rough surface and the simulation of dilute two-phase flow, is successful in the simulation of slurry flow and particles motion in multilevel rough gap. The research about two phase flow in the multilevel rough gap helps to reveal the mechanism of the production of the defects on the wafer surface, and improve the microstructure design of pad and conditioning technique.

Key words: Chemical mechanical planarization, Micro two-phase flow, Rough surface