Role of Potassium Tolyltriazole as an Inhibitor in H2O2-Based Slurry on Cu/Ru Patterned Wafer CMP

Abstract

In the process of chemical mechanical planarization (CMP) during copper interconnection fabrication, the inhibitor in the copper slurry plays an important role in obtaining a good planar surface after CMP. In this paper, a kind of corrosion inhibitor TTAK was introduced in H2O2-based alkaline slurry. The experimental results show that the addition of TTAK can effectively reduce the removal rate (RR) and static corrosion rate (SER) of copper. With the increase of TTAK concentration, the passivation effect is enhanced. The passivation mechanism of TTAK was characterized by electrochemistry and X-ray photoelectron spectroscopy (XPS). The results show that in the H2O2-Gly system (alkaline), TTAK can reduce the corrosion rate and removal rate of copper by absorbing on copper surface to form passivation film. On the contrary, it has no significant influence on Ru. In addition, the dishing and erosion of Ru/Cu structure based patterned wafers were further tested. The experimental results show that the introduction of TTAK can effectively reduce the dishing and erosion depth of different line width and spacing.