A model of material removal and post process surface topography for copper CMP
Increasing systemic error during copper CMP (Chemical Mechanical Planarization) is due to the uneven surfacetopography generated during the process. A mechanistic model based on a fundamental understanding of the processconstituents was proposed to predict material removal rates and the post CMP topography. Two synergisticmechanisms were proposed: 1) chemically dominant behavior is explained by the repetitive removal and formation ofa protective layer on copper surface and chemical dissolution during the process, 2) mechanically dominant removalmechanism is due to the material behavior of copper at the nano-scale and subsequent oxidation and removal of theplastically deformed copper. As a step forward to optimize the process and the manufacturing system, this model wasextended to explain pattern dependent variability during copper CMP.