Theoretical and experimental investigation of conditioner design factors on tribology and removal rate in copper chemical mechanical planarization

Three theories connecting conditioning with material removal rates by the coefficient of friction are proposed and experimentally verified. The conditioning theory is employed to provide a specific prediction on how the number of active diamonds, cut rate, and cut furrow geometry affect pad surface abruptness. The same surface abruptness parameter was a factor in both the coefficient of friction and removal rate theories. The theory predicts a priori that friction and removal rate should decrease as the conditioned surface became less abrupt. Simple models of cut rate and active diamond count further indicate that abruptness should decrease with increasing conditioner load. Mitsubishi Materials Corporation conditioners with 60, 100, and 200 grit sizes are used to test the theory in an experiment in which conditioner load is varied from light to heavy. Polishing experiments and pad profilometry verified the main predictions of the theory.