Host: Ara Philipossian, Chemical and Environmental Engineering, University of Arizona
Presentation by: Changhong Wu, PhD candidate, and Ara Philipossian (dissertation adviser), Chemical and Environmental Engineering, University of Arizona
Topic title: "Pad Surface Thermal Management during Copper Chemical Mechanical Planarization"
Abstract: A pad surface thermal management system is developed to improve copper removal rate within wafer non-uniformity by locally adjusting the pad surface temperature. The system consists of one or more thermal transfer modules, which contact the pad surface during polishing. Hot or cold water circulates between the thermal transfer module and an external heater or cooler. As the module is placed on the pad surface, heat conduction occurs between the module and the pad surface, producing a localized surface with higher or lower temperatures. It is therefore expected that the local removal rates will change accordingly since copper chemical mechanical planarization (CMP) is highly sensitive to temperature. In this study, the system is used to adjust the “center-fast” removal rate profile to illustrate its effect during copper CMP. Results show that, when two thermal transfer modules are employed, local removal rates on the wafer center region decrease significantly while maintaining the removal rates on the wafer edge region thus resulting in improved within wafer non-uniformity.