Effect of novel green inhibitor on corrosion and chemical mechanical polishing properties of cobalt in alkaline slurry

The galvanic corrosion between copper (Cu) and cobalt (Co) has been widely concerned. Generally, the method of increasing Co corrosion potential is adopted to reduce the corrosion potential difference between Cu/Co. In this paper, the inhibitory mechanism of phytic acid on corrosion of Co, a new green corrosion inhibitor, was studied systematically. The inhibitory effect of phytic acid on Co was studied by dynamic and static electrochemical experiment. The corrosion potential of Co under static condition is higher than that of dynamic condition. The chemical mechanical polishing (CMP) experiments and atomic force microscopy (AFM) tests showed that the introduction of phytic acid increased the material removal rate (from 279 angstrom/min to 520 angstrom/min) and surface quality (Rq from 1.74 nm to 0.29 nm) of Co, respectively. The results of Nikon microscope and scanning electron microscope (SEM) showed that phytic acid had inhibitory effect on Co. XPS experimental results showed that the complexation reaction between PA and Co2+ generated macromolecular substance Co-PA, which was combined with other substances on the surface of Co and formed a new passivation layer to protect the surface of Co from corrosion. The chemical bond between Co2+ and PA is easy to move, which increases the RR of Co.