Vibration characteristics of the capillary in ultrasonic wire bonders

C. M. Hu, N. Q. Guo, H. J. Du, R. M. Lin, M. Chen

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3 Citations (Scopus)


Currently ultrasonic wire bonders with precision capillary tips are widely used in the packaging industry for bonding wires to ICs and circuits. However, the quality and strength of a bond are affected significantly by the vibration of the bonding capillary. It is, therefore, necessary to study the vibration characteristics of the capillary for better understanding and for developing a non-perturbative and low-cost monitoring device for improving bonding quality control. In this paper, the vibration characteristics of the capillary are presented in terms of natural frequency and vibration modes using finite-element models. The predicted displacement profile along the capillary is compared with the measurement using a non-contact laser interferometer. In general, a good agreement between the prediction and measurement is obtained, and it shows that the interferometer may be a good monitoring tool for characterization of capillary tip vibration, as well as providing a reference for other monitoring devices. JMES265

Original languageEnglish
Pages (from-to)897-903
Number of pages7
JournalProceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science
Issue number8
Publication statusPublished - Aug 2007
Externally publishedYes


  • Vibration of the capillary
  • Wire bonding

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