Effect of iodine on the corrosion of Au–Al wire bonds. (August 2015)

• Record Type: Journal Article
• Authors: Verdingovas, Vadimas; Müller, Lutz; Jellesen, Morten Stendahl; Grumsen, Flemming Bjerg; Ambat, Rajan
• Is Part Of: Corrosion science. Volume 97(2015)
• Page Start: 161
• Page End: 171
• Publication Date: 2015-08
• Subjects: A. Aluminium -- A. Electronic materials -- A. Intermetallics -- B. Polarisation -- B. X-ray diffraction -- C. Interfaces; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2015.05.003
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Formation of Au–Al intermetallics during heat treatment are investigated in situ by XRD. Increase of RH in iodine containing environment accelerates the corrosion of Au–Al. Corrosion resistance of Au–Al decreases with increase of Al in the intermetallic phase. Failures are primarily attributed to corrosion of Al at the bond interface and in the intermetallic phases. Chemical reactions describing corrosion mechanism are suggested. 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 (1 mg/L) at 85 °C with varying relative humidity, and 500 mg/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.