Atomistic Insights into the Copper Oxidation Reactions for the CeO<sub>2</sub>-Cu Interface Using First-Principles Molecular Dynamics Simulations

The reaction pathways of Cu oxidation by the chemical mechanical polishing (CMP) slurry containing ceria (CeO) abrasive grains were theoretically investigated.First-principles molecular dynamics (FPMD) simulations were employed to analyze the reaction pathways between a CeO surface and a Cu surface.As a result, the following reactions were observed: chemical bonds between CeO and Cu were formed, electron transfer from Cu atoms to Ce atoms occurred, a water molecule dissociated on the CeO surface to form a proton and an OH ion, and the generated OH ion formed Cu-O bonds with the oxidized Cu atoms.The candidate reaction pathways for Cu oxidation, including those observed in FPMD simulations, were further analyzed by constructing energy diagrams using density functional theory (DFT) calculations.As a result, the reaction pathway observed in the FPMD simulation was identified as the most likely candidate, having the lowest activation energy and the lowest final structure energy.These results indicate that the oxidation reaction pathways of Cu in the slurry containing CeO abrasive grains involve electron transfer through the formation of chemical bonds between CeO and Cu, as well as the supply of oxygen atoms derived from water to Cu atoms.