Effects of Hydrogen Peroxide on Chemical Mechanical Polishing of Copper Surface: Exploration of Reaction Pathways with Molecular Dynamics Simulation and Activation Energies Calculation

The mechanisms of chemical mechanical polishing (CMP) of copper (Cu) surface using a slurry containing hydrogen peroxide (H2O2) and silica abrasive grains were theoretically investigated. First, molecular dynamics (MD) simulations using ReaxFF were used to analyze reactions that remove Cu atoms from the Cu(111) surface. At the Cu/H2O2 interface, Cu atoms were oxidized by forming Cu-O atoms were oxidized. In the second pathway, the atomic arrangement around the oxidized Cu atoms was disordered caused by surface vacancies. In relation to the first reaction pathway, activation energies were calculated to study the effects of the oxidation of Cu atoms on the Cu removal reactions. The results showed that the lowest activation energy was obtained when the structure in which neighboring Cu atoms were most oxidized, which supported the results of the MD simulations. The findings of this study indicate that the oxidation degree of adjacent Cu atoms and the atomic arrangement of the Cu surface affect the Cu removal reactions.