A new method to enhance the tip vibration amplitude output of the high frequency piezoelectric ultrasonic transducer used in the thermosonic bonding

摘要

The vibration amplitude output of the high frequency piezoelectric ultrasonic transducer used in the thermosonic bonding system can be reduced owing to many factors, among which the mounting clamp, taking charge of installing the whole transducer on the mounting bracket in bonding machine, is one such factor. To minimize the negative effect of the coupling between the transducer and the mounting bracket through the mounting clamp, and enhance the vibration amplitude output of the transducer, a new kind of flexible mounting clamp is proposed, which combines the traditional mounting clamp and the flexure hinge. Several high frequency ultrasonic transducers with different flexible clamps were designed and fabricated. A measurement system was specially set up to investigate the vibration characteristics of the transducers. Results show that the proposed flexible mounting clamps are able to increase the tip vibration amplitude output of the transducer significantly, whether the transducer vibrates at resonance or not. The promotion effect is closely related to the compliance and the decoupling potential of the clamp. The method newly proposed is a meaningful and useful attempt, and it also can be used for the ultrasonic transducers in other applications. (C) 2019 Elsevier B.V. All rights reserved.