Methodology to characterize the capillary tip ultrasonic vibration with laser Doppler vibrometer

This paper demonstrates the capillary ultrasonic characterization methodology with laser Doppler vibrometer (LDV). Total five capillaries with different body designs with same tip dimensions were evaluated. Using the energy conservation theory, it is derived that capillary with higher tip velocity at bonding represent better ultrasonic power transmission to the bonding interface. This is with the assumptions that no IMC formation and the energy loss through friction is constant. Capillary tip velocity is measured with the bonding on Alu pad and Silicon chip at room temperature in order to prevent the IMC formation. Besides, actual bonding is done on BGA package at 150°C to measure the ball shear and NSOP rate. From the results, it showed that with the increasd of tip velocity on Alu pad and Silicon chip, ball shear has increased and NSOP rate has reduced.