Polydopamine-coated cerium oxide core-shell nanoparticles for efficient and non-damaging chemical-mechanical polishing

Abstract

Chemical mechanical polishing (CMP) represents one of the most important steps in the manufacturing of integrated circuits and high surface quality is always required for the CMP processes of shallow trench isolation (STI) structures. Herein, a new series of polydopamine (PDA)-coated cerium oxide core-shell nanoparticles has been developed as efficient and non-damaging abrasives for CMP of SiO2 on the surface of silicon wafers. The composite abrasives with the structure of SiO2@CeO2@PDA have been fabricated in a simple manner and thoroughly characterized using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The SiO2 core enhances the content of Ce3+ in the abrasives, while the water-soluble PDA layer facilitates the interaction between the abrasives and SiO2 dielectrics. As a result, the wafers polished by SiO2@CeO2@PDA not only achieved a high polishing rate but also exhibited a high surface quality (Ra = 0.109). This study not only presents a new efficient and non-damaging type of cerium oxide abrasives for CMP, but also highlights the potential of the surface coordination strategy in the fabrication of advanced abrasives for the manufacturing of integrated circuits.