Composite Polymer-Core Silica-Shell Abrasive Particles during Oxide CMP

Chemical mechanical planarization (CMP) is a triboelectrochemical process dominated by mechanical and chemical-assisted wear. The choice of abrasive used in this process is of fundamental importance. In this study, oxide CMP using novel polymer-core silica-shell composites were compared with conventional colloidal silica as abrasives in terms of removal rate and surface finishing. The composite particles were achieved by either creating chemical bonds by silane coupling agents or tuning the pH to form electrostatic attractive interactions between the core and the shell. We used oxide CMP as a convenient test vehicle for defectivity characterization and comparison between different abrasives. Due to the higher complexity of the composite abrasive with respect to the simple silica particle-wafer system, we combined different surface analysis techniques with methods of defect quantification and enhancement. Overall, fewer and shallower scratches were detected for the composites with respect to colloidal silica.