Development of polystyrene/polyaniline/ceria (PS/PANI/CeO2) multi-component abrasives for photochemical mechanical polishing/planarization applications

Abstract

Tri-layer nanostructured polystyrene/polyaniline/ceria (PS/PANI/CeO2) multi-component composites were developed as functionalized particle abrasives for improved photochemical mechanical polishing/planarization (PCMP) applications. The physicochemical characteristics of the PS/PANI/CeO2 and PS/CeO2 samples were examined by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Flourier-transform infrared spectroscopy, UV–visible spectrophotometer, photoluminescence spectroscopy, and thermogravimetric analysis. Ultra-smooth and defect-free surfaces with ultra-low roughness (0.12 nm Ra, 0.16 nm RMS) were achieved after PCMP with polymer/CeO2 hybrid abrasives. It might be attributed to the enlarged contact area and the decreased indention depth between the particle and the surface, possibly originating from the elastic polymer cores. The synergy of the PANI conductive polymer and the CeO2 particle photocatalyst contributed to improving the separation efficiency of photo-generated carriers, thereby enhancing the photochemical oxidation activity. As expected, the tri-layer PS/PANI/CeO2 abrasives achieved a ca. 69% increment of material removal rate compared to the PS/CeO2. The interfacial contact model and material modification/removal mechanism of the PS/PANI/CeO2 multi-component tri-layer abrasives during PCMP processes were also discussed. The aim of this work is expected to provide guidance for the design and promising applications of novel polymer/CeO2 composite abrasives in advanced CMP, PCMP, electrochemical mechanical polishing (ECMP), and photoelectrochemically combined mechanical polishing (PECMP).