芯片键合纵弯复合超声换能器的设计与试验

A piezoelectric transducer with longitudinal-flexural composite ultrasonic mode was developed in order to solve the problem that the ultrasonic energy with one-dimensional longitudinal mode causes insufficient bonding area during chip bonding. The transducer can generate composite ultrasonic vibration to replace the conventional longitudinal vibration. The finite element simulation by ANSYS Workbench was employed to conduct the modal analysis and harmonic response analysis of transducer. The resonant frequency and mode shape of the longitudinal and flexural modes were obtained. The longitudinal and the flexural vibration modes were degenerated by adjusting the size of the transducer structure. The frequency and impedance testing of the prototype were conducted by impedance analyzer. The longitudinal and flexural amplitude of the transducer were measured by laser Doppler vibrometer. The experimental results accorded with the finite element calculation. The amplitude of the longitudinal and flexural vibration showed an upward tendency with the increasing of driving voltage. Results prove that the designed transducer can achieve the longitudinal-flexural composite vibration.