Power and Interface Features of Thermosonic Flip-Chip Bonding

Driving voltage and current signals of piezoceramic transducer were measured directly by using digital storage oscilloscope, and interface microcharacteristics of the specimens of flip-chip bonding were inspected by using a transmission electron microscope. Results show such a trend that power curves of badly bonding were much lower than that of hard bonding, and indicated a monitoring system of ultrasonic bonding reliability. The acceleration of ultrasonic vibration was about several ten thousand times as acceleration of gravity, which activates dislocations inside the metal crystalline lattice which act as the fast diffusion channels. Dislocation diffusion is more prominent than the crystal diffusion when the temperature is low. Differing from thermal melting mechanism of the reflow bonding, the ultrasonic bonding is much faster than the reflow solder bonding.