Study of electrodes design for electro-kinetic force chemical mechanical polishing of copper planarization

Chemical Mechanical Polishing/Planarization (CMP) has been recognized as an irreplaceable technology of approaching the IC fabrication with global planarization. CMP affects the final properties of IC production so that the process has been improved for efficient and defect-free surface demands. This study aims to develop a novel Electro-Kinetic Force assisted CMP (EKF-CMP) with the well-designed electrodes simulated by the commercial software, COMSOL Multiphysics, to enhance the electro-osmosis flow in during the process. Experiments of EKF-CMP have been performed on Cu-blanket and Cu-patterned wafer (SEMATECH 854AZ) planarization. Results of Cu blanket CMP show that the surface roughness has been achieved from Sa 8.62nm to 7.72nm. Moreover, the EKF-CMP has also reduced dishing on 100/100, 50/50, and 10/90 micron Cu-patterns. Future application can be focused on the suitable pad and slurry adaptable to such EKF-CMP process.