Impact of CMP consumables on copper metallization reliability

Over the past few years, the chemical mechanical planarization (CMP) community has systematically characterized the device reliability issues associated with the introduction of copper metallization into integrated circuit fabrication. To gain further understanding of the impact of CMP processing on device performance, this paper reports in detail the interactions of simulated copper slurries and pristine segmented polyurethanes. These studies clearly show that polyurethane is fundamentally incompatible with some of the chemicals used in copper CMP, such as hydrogen peroxide. Experimental copper polishing data on both polyurethane and polyolefin-based pads are compared. The pad performance differences between the polyurethane and polyolefin-based pads are explained based on the chemistry of the base polymers used in the pad fabrication. These results are incorporated into the design and fabrication of a new class of polyolefins-based application specific pads.