Pad conditioning in chemical mechanical polishing: a conditioning density distribution model to predict pad surface shape

Abstract

Diamond disc pad conditioning is traditionally employed to restore pad planarity and surface roughness in chemical mechanical polishing (or planarisation) (CMP). In this paper, a conditioning density distribution model is developed to predict the pad surface shape resulted from the diamond disc conditioning in CMP. A kinematic study is carried out to calculate and simulate the diamond grit trajectories. An analytical model is then proposed to correlate the conditioning density distribution with the wear of the polishing pad. In this study conditioner design is considered while function defined sweeping profiles and a visual measure of conditioner-pad contact distribution are introduced. Furthermore, the pad surface shape is predicted by the model and compared with experimental data. Results show that the model is effective to predict the pad surface shape.