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 with SiO₂@CeO₂@PDA not only achieved a high polishing rate, but also exhibited a high surface quality (R_a = 0.109). This study not only presents a new efficient and non-damaging type of cerium oxide abrasive for CMP, but also highlights the potential of the surface coordination strategy in the fabrication of advanced abrasives for the manufacturing of integrated circuits.