Authors: J.S. Kim, J.M. Kim, S.I. Lee, E.J. Lim
Affilation: University of Seoul, Korea
Pages: 79 - 82
Keywords: semiconductor packaging, ultrasonic transducer, topology optimization
In this study, we introduce the method of topology optimization for piezoelectric transducers including ultrasonic tool horns for flip chip or wire bonding. Topology optimization performs an optimization with the objective function regardless of initial topology of the model. The objective function is prepared with shifting the resonance frequency for a longitudinal vibration mode of the transducers. The solid isotropic material with penalization (SIMP) method is used to formulate topology optimization and optimal criteria (OC) method is introduced for the update scheme. Those schemes are implemented by MATLAB and finite element model is established and calculated in COMSOL. The objective longitudinal mode at the resonance frequency is tracked using modal assurance criterion (MAC). After the optimization process, we can compare the converged design shapes between 2D and 3D models. Considering the availability of the design, we manufacture two types of ultrasonic transducers based on the 3D optimization results. The vibration displacements of the transducers are measured by laser vibrometer. The resonance frequency and the power difference between the design models and the evaluation prototypes are less than 1%. Also we test the transducers in the accelerated operation environment more than 1,500 equivalent hours to check the reliability of the transducers.