Atomic Diffusion Properties in Al/Ni & Au/Al Bond Interface

Cross section in bonding point was produced by rubbing and polishing metallographic sample with metallographic inlaying powder. Cross section characteristics on ultrasonic bonded micro-interface (including Au/Al, Al/Ni) were tested by means of scanning electron microscope (JSM-6360LV) and EDS (EDAX2000). Lift-off characteristics at bonding micro-interface of thermosonic bond were observed by using SEM. Results show that atomic diffusion at the bonded interface was occurred each other. Thickness of Au/Al & Al/Ni interface was about 1-3 micron under ultrasonic and thermal energy. Inter-metallic compounds in Au/Al & Al/Ni interface were undiscovered under ultrasonic bonding in very short time that was the order of millisecond. Fracture morphology of lift-off interface was dimpled. Tensile fracture was generated by pull-test not only in bonded interface but also in basis material, and bonded strength at interface was strengthened by diffused atom from another side