Tribological and kinetic characterization of 300-mm copper chemical mechanical planarization process

The tribological and kinetic attributes of 300-mm copper chemical mechanical planarization process were characterized in this study. Coefficient of friction (COF) ranged from 0.39 to 0.59 for the Cabot Microelectronics Corporation D100 concentrically grooved pad, indicating that boundary lubrication was the dominant tribological mechanism. In comparison, COF decreased sharply from 0.55 to 0.03 for the Dow Electronic Materials IC1000 K-groove pad, indicating that the tribological mechanism transitioned from boundary lubrication to partial lubrication. For both pads, copper removal rate exhibited highly non-Prestonian behavior. A two-step modified Langmuir-Hinshelwood model was used to simulate copper removal rate, wafer surface reaction temperature, as well as chemical and mechanical rate constants. The simulated copper removal rates agreed very well with the experimental values. The simulated chemical rate constant to mechanical rate constant Tatios indicated that the IC1000 pad generally produced a more mechanically controlled removal mechanism in this study.