Evaluation of dynamic bonding stress and interlayer cracking using a combo sensor

Crack defect in the interlayers of semiconductor chips due to assembly stress can be a serious problem. To analyze the crack-generating stress, we fabricated a combo sensor that enables simultaneous evaluation of stress and cracking under the bonding pad. Dynamic analysis of the bonding process with this sensor in situ showed that the cracks are generated by stress concentration in alloy aggregates that form during the initial stage of ultrasonic bonding.