The effect of hydrogen peroxide on frictional and thermal behaviors in a citric acid-based copper chemical mechanical planarization slurry

Abstract

The effect of H2O2 oil the frictional and thermal behaviors of a citric acid-based slurry was characterized during Cu polishing. As the H2O2 concentration increased, the static and dynamic etching rates gradually decreased. The removal rate of Cu initially increased and reached the maximum value at a slurry concentration of 5 vol % H2O2 after which the removal rate gradually decreased with further increases in H2O2 due to the formation of a thick Cu oxide layer. The frictional force gradually decreased with increased H2O2 concentration. The friction force was high in spite of the low removal rate in the 1 vol % H2O2 Slurry. The pad temperature changed as a function of H2O2 concentration in a manner similar to at that of the friction force. The higher pad temperature resulted in higher static etching and corrosion rates of Cu during polishing.