Reconditioning-free polishing for interlayer-dielectric planarization

In chemical mechanical polishing (CMP) using a colloidal silica slurry with a pH of 10–11 for interlayer-dielectric (ILD) planarization, the removal rate of the oxide film drops off rapidly because the pad surface becomes flat during a CMP process. Thus we must recondition the polishing pad surface in order to obtain the rough polishing pad surface. In result, we can maintain a constant removal rate of the oxide film during the life time of the pad. We clarified that the alteration of the polishing pad surface was caused by the KOH solution in a conventional slurry. We also found that our newly developed MnO 2 slurry could prevent the alteration of the polishing pad surface in reconditioning-free CMP.