Composite Polymer Core - Silica Shell Abrasive Particles During Oxide CMP: A Defectivity Study

Abstract

Chemical Mechanical Planarization (CMP) is a triboelectrochemical process dominated by mechanical and chemical-assisted wear. The choice of the abrasive is of fundamental importance. Oxide CMP results using two different 350 nm polymer-core / 30 nm colloidal silica-shell composite abrasive particles are compared with oxide CMP performances of 30 nm and 90 nm colloidal silica abrasives in terms of removal rate and surface finishing. The composites are achieved by either creating chemical bonds by silane coupling agents or tuning the pH in order to form electrostatic attractive interactions between core and shell. Oxide CMP is considered as an easy test vehicle for defectivity characterization and comparison between different abrasives providing the same oxide thickness removed. Due to the higher complexity of the composite abrasive with respect to the simple silica particle- wafer system, we combine different surface analysis techniques with m ethods of defect quantification and enhancement. Fewer and shallower scratches are detected for the composites with respect to colloidal silica.