Inhibition Effect of TT-LYK on Cu Corrosion and Galvanic Corrosion between Cu and Co during CMP in Alkaline Slurry

Cu corrosion and galvanic corrosion between Cu and Co are two challenging issues during the chemical mechanical polishing (CMP) process in the ultra large scale integration (ULSI) technology. The effect of novel inhibitor TT-LYK on Cu corrosion and galvanic corrosion between Cu and Co in alkaline slurrywas investigated under both static and dynamic conditions. Various analytical techniques were used to elucidate the corrosion inhibition mechanism of TT-LYK on Cu. Results showed that both static etching rate (SER) and removal rate (RR) of Cu during CMP decreased with the increase of concentration of TT-LYK. From potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) measurements, it was found that the corrosion inhibition effect on Cu may result from the adsorption of Cu(I)-TT-LYK passivating film on Cu surface. In order to characterize the effect of galvanic corrosion, the corrosion potential difference (Delta E) between Cu and Co was measured during both static and dynamic condition. It was apparently seen from the results that the galvanic corrosion under dynamic conditions was significantly suppressed compared with the static cases. It revealed that if the experiments had only been conducted under static conditions, the results would have been considerably misleading. (C) The Author(s) 2019. Published by ECS.