The Synergistic Inhibitory Effect and DFT Study of SAS60 and TAZ on Copper Chemical Mechanical Polishing

Abstract The chemical mechanical planarization (CMP) of multi-layer copper wires in giant-scale integrated circuits (GLSI) is one of the crucial processes for advancing microelectronic technology. The inhibitor is an important factor for achieving the planarization of copper wafers, and the addition of surfactant can improve the surface quality, so the combined use of inhibitor and surfactant has been a hot spot of research. In this study, the effect of sodium secondary alkyl sulfonate (SAS60) and 1,2,4-triazole (TAZ) on copper surface when used in combination is analyzed in depth through polishing experiments, electrochemical experiments, contact angle experiments and surface characterization tests. The mechanism of action of SAS60 and TAZ is discussed using density functional theory (DFT) method. The results of the study show that the synergistic use of SAS60 and TAZ can achieve good effects: reduce the polishing rate of copper, improve the wettability, reduce the surface defects, and reduce the surface roughness. Furthermore, it was shown that SAS60 is more readily adsorbed on the copper surface than TAZ, and when TAZ and SAS60 are used in combination, the adsorption layer is denser and more stable, which helps to elucidate the synergistic effect of surfactants and inhibitors at the microscopic level.