Effect of iodine on the corrosion of Au–Al wire bonds

Abstract

Corrosion study was performed on Au–Al wire bonds, thin layers of sputter deposited Au and Al, and Au–Al intermetallic nuggets. The test environment was iodine-vapour in air (1mg/L) at 85°C with varying relative humidity, and 500mg/L of KI in water. GDOES, XRD, SEM EDS, wire bond shear, and electrochemical testing were used to characterize the samples. Failures of Au–Al wire bonds were found to be primarily attributed to the corrosion of Al via formation of Al iodides and consequent formation of Al oxides and/or hydroxides. Most susceptible to corrosion are Al metallization and Al rich intermetallic phases.