Simulation on Temperature Distribution in Chemical Mechanical Polishing

Abstract

Temperature rise has two-edged influences on chemical mechanical polishing (CMP) process: temperature-rise facilitates the chemical activity and the motion of the nano particles contained in the slurry through which material removal ratio (MRR) is enhanced; to the other side of the same coin, however, it will soften the pad surface and subsequently reduce the MRR. Thus the research on temperature distribution of CMP process will be conducive to discovering the mechanism of polishing, and acquiring stable MRR and improving surface quality. With the help of the knowledge of tribology, hydrodynamics, and thermodynamics, flow equation considering the temperature variation in the fine step of CMP process, wherein high surface quality is the main concern and usually operates in contact free state, is set up, based on which the temperature field in contact is investigated in detail by taking advantage of the simulation technique, and the heat energy production and transition relations are obtained. Due to the slurry used, a small viscous heating effect is acknowledged by simulated results, and the temperature rise is negligible in contact-free flows, which is very conducive to the promotion of the final polished wafer/disk surfaces. The research will surely shed some lights in the mechanism of CMP and lay a feasible foundation for possible future utilization.