Nanotopography impact of surfactant concentration and molecular weight of nano-ceria slurry on remaining oxide thickness variation after shallow trench isolation chemical mechanical polishing

Abstract

It has been reported that wafer nanotopography has a substantial impact on oxide film thickness variation after chemical mechanical polishing (CMP). Currently, shallow trench isolation (STI) is the preferred isolation scheme for device manufacturing, where STI CMP has become an essential process. Studies on nanotopography effects when using fumed silica slurries have been reported. This research examines the impact of nanotopography on the remaining oxide film thickness variation with varying surfactant concentrations in and molecular weights of the nano-ceria slurries used in STI CMP. Higher surfactant concentration and molecular weight lead to higher remaining oxide film thickness variation induced by wafer nanotopography.