A novel ultrasonic transducer with multiple vibrations in microelectronic packaging

Abstract

Ultrasonic wire bonding is a typical packaging for semiconductor devices. Compared with single longitudinal transducer, we propose a novel ultrasonic transducer with multiple vibrations for the microelectronic packaging. The transducer is designed to excite the longitudinal and bending vibration individually or simultaneously. By simulation calculation, three longitudinal vibrations and a bending vibration is attained in the same node flange. The transducer structure is established by optimizing a balance and a Z-shaped flange, which can achieve the optimal modal shape. Under the 10 kg·cm torque for clamping the piezoelectrics stacked, the frequency of longitudinal vibration is 64.8 kHz 103.4 kHz 142.8 kHz and bending vibrations is 70.5 kHz. A dual channel driver with Field Programmable Gate Array (FPGA) and Digital Signal Processing (DSP) controller is self-developed to excite the multiple vibrations. In experiment, each vibration is excited individually, switched or simultaneously. It is found that all vibration for each operating modes is higher than 1 µm, and the vibration profile can be controlled as a rectangle or parallelogram, which has potential to be a new bonding process.