Supramolecular surface modification of ceria nanoparticles for enhanced chemical mechanical planarization performance in shallow trench isolation

Abstract

Chemical mechanical planarization (CMP) is an indispensable technique for achieving global planarization in shallow trench isolation (STI) structures, a critical component in modern integrated circuits. With the continuous advancement of technology and increasing demands for chip performance, the critical metrics of STI CMP processes have become increasingly stringent, placing higher requirements on the performance of polishing slurries. In particular, SiO₂/Si₃N₄ removal rate selectivity (RRS) and surface flatness directly impact product quality and yield. In this study, we present a supramolecular strategy for tailoring ceria (CeO₂) surfaces to enhance CMP performance, especially SiO₂/Si₃N₄ removal rate selectivity (RRS) and surface flatness. Specifically, we functionalized CeO₂ nanoparticles with β-cyclodextrin (β-CD), a macrocyclic supramolecular host, to modulate surface properties. This modification not only improves the colloidal stability of the resulting CeO₂ slurries but also endows them with three key advantages: (1) elevated material removal rate (MRR), (2) outstanding post-polishing surface quality, and (3) significantly enhanced SiO₂/Si₃N₄ RRS. Furthermore, the β-CD-modified CeO₂ surface serves as a versatile platform for secondary functionalization with small molecules. By incorporating glutamic acid as a co-modifier, we demonstrate synergistic improvement in SiO₂/Si₃N₄ RRS, highlighting the cooperative effects between supramolecular and molecular additives. This work establishes a facile supramolecular approach to engineer high-performance CeO₂-based CMP slurries for STI applications. More broadly, it validates the potential of hybrid modification strategies—combining macrocyclic hosts with small-molecule guests—to precisely tune abrasive/surface interactions and advance CMP technology.