Electrochemical corrosion of interconnect materials by residual reductants

Reductants are widely used in up-to-date interconnect fabrication processes. Given that electrochemical corrosion of the interconnections may occur in humid circumstances under current stressing, this study explores the electrochemical properties of common interconnect materials, Cu and Ag, in the aqueous solutions of formic acid, glycol or ascorbic acid with various concentrations. Experimental results show that there exists no passivation stage on the polarization curves of Cu and Ag in those reductive solutions. Chronoamperometric study indicates that ascorbic acid corrodes Ag faster than the other reductants, while formic acid is most corrosive for Cu.