Development of novel ultrasonic transducers for microelectronics packaging

Novel high-frequency ultrasonic transducers have been developed in order to provide faster, more repeatable and stronger microelectronics bonding technology, and fine-pitch packaging can be accomplished by these transducers. The analytical model of the transducer system is established on the basis of electromechanical equivalent circuitry theory, vibration theory and wave theory, which lays the foundation for determining the initial topological information of the ultrasonic transducer. By use of finite element method (FEM), the dynamic characteristics of components are investigated. The resonance frequency, vibration displacement nodes and rule of ultrasonic energy transmission are acquired by making modal and harmonic analysis. Through optimum design by considering the piezoelectric effect, the dimensions of ultrasonic transducer have been gained finally. The prototyped transducer is tested through the impedance analyzer and laser Doppler vibrometer, which proves remarkable resemblance with the theory and FEM. The experimental results also show that there are no undesirable vibration modes around the working frequency, thus it becomes convenient for the vibration control.