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 surface topography generated during the process. A mechanistic model based on a fundamental understanding of the process constituents was proposed to predict material removal rates and the post CMP topography. Two synergistic mechanisms were proposed: 1) chemically dominant behavior is explained by the repetitive removal and formation of a protective layer on copper surface and chemical dissolution during the process, 2) mechanically dominant removal mechanism is due to the material behavior of copper at the nano-scale and subsequent oxidation and removal of the plastically deformed copper. As a step forward to optimize the process and the manufacturing system, this model was extended to explain pattern dependent variability during copper CMP.