Deformation Behavior of Thick Aluminum Wire during Ultrasonic Bonding

Abstract

The deformation behavior of thick Al wires and the expansion behavior of the bond area during ultrasonic wedge bonding to Al–Si, Si and SiO₂ substrates were measured simultaneously in detail with a high-speed measuring system. The deformation of the wire by the application of the bonding force is completed immediately. The deformation restarts by the application of the ultrasonic vibration. The deformation induced by applying the bonding force consists of only elastic component, whereas that by ultrasonic vibration consists of only plastic component. The Al wire is not work-hardened by the plastic deformation during application of ultrasonic vibration. The adhered area expands to the direction perpendicular to the ultrasonic vibration. The evolution of the wire deformation behavior and the expansion of the adhered area show an intimate correlation with each other.