Characterization of Intermetallic Growth in Gold Ballbonds on Aluminum Metallization

Abstract

The objective of this project is to study the capability of gold wire bonding process by investigating the intermetallic growth between gold ball bonds and aluminum bond pad. The study includes applying thermal storage conditions at 150 °C and 200 °C at various intervals time. The relationships between electrical resistance and intermetallic growth were also investigated. Process decapsulation and Field Emission Scanning Electron Microscopy were used to accurately determine the intermetallic coverage of gold ball and aluminum bond pad. Then Field Emission Scanning Electron Microscopy was used to obtain the micrograph image of intermetallic growth, Kirkendall Voiding and followed by intermetallic phase by using EDX for cross sectioned sample. The results indicated that the electrical resistance and magnitude of growth in intermetallic Al-Au is proportional to the amount duration of curing time at aging temperature. Under thermal aging, the gold wire ball bonds show formation of Kirkendall voids and different intermetallic phases apart from intermetallic compound growth.