Ultrasonic power features of wire bonding and thermosonic flip chip bonding in microelectronics packaging

  • Jun-hui Li (李军辉)Email author
  • Lei Han (韩 雷)
  • Jue Zhong (钟 掘)


The driving voltage and current signals of piezoceramic transducer (PZT) were measured directly by designing circuits from ultrasonic generator and using a data acquisition software system. The input impedance and power of PZT were investigated by using root mean square (RMS) calculation. The vibration driven by high frequency was tested by laser Doppler vibrometer (PSV-400-M2). And the thermosonic bonding features were observed by scanning electron microscope (JSM-6360LV). The results show that the input power of bonding is lower than that of no load. The input impedance of bonding is greater than that of no load. Nonlinear phase, plastic flow and expansion period, and strengthening bonding process are shown in the impedance and power curves. The ultrasonic power is in direct proportion to the vibration displacement driven by the power, and greater displacements driven by high power (>5 W) result in welding failure phenomena, such as crack, break, and peeling off in wedge bonding. For thermosonic flip chip bonding, the high power decreases position precision of bonding or results in slippage and rotation phenomena of bumps. To improve reliability and precision of thermosonic bonding, the low ultrasonic power (about 1–5 W) should be chosen.

Key words

ultrasonic power wedge bonding thermosonic flip chip input impedance failure 


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Copyright information

© Central South University Press and Springer-Verlag GmbH 2008

Authors and Affiliations

  • Jun-hui Li (李军辉)
    • 1
    • 2
    • 3
    Email author
  • Lei Han (韩 雷)
    • 1
    • 2
  • Jue Zhong (钟 掘)
    • 1
    • 2
  1. 1.School of Mechanical and Electronical EngineeringCentral South UniversityChangshaChina
  2. 2.Key Laboratory of Modern Complex Equipment Design and Extreme Manufacturing of Ministry of EducationChangshaChina
  3. 3.State Key Laboratory of Digital Manufacturing Equipment and TechnologyHuazhong University Science and TechnologyWuhanChina

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