A model of pad-abrasive interactions in chemical mechanical polishing

Abstract

In model descriptions of CMP, slurry abrasives stick to and release from the polishing pad. This model extension predicts how pad-abrasive interactions depend on abrasive size. The prediction is compared to five sets of experimental data for systems using silica or alumina abrasives and different pads to polish copper, tungsten, or tantalum under various experimental conditions. The finding that larger particles are harder to dislodge from the pad than smaller ones holds over two orders of magnitude in abrasive diameter. This affects material removal rates which depend on the number of abrasive particles attached to the pad. © 2007 The Electrochemical Society.