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

作　　者：李军辉 韩雷 钟掘 

机构地区：[1]School of Mechanical and Electronical Engineering, Central South University [2]Key Laboratory of Modern Complex Equipment Design and Extreme Manufacturing of Ministry of Education, Changsha 410083, China [3]State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University Science and Technology, Wuhan 430074, China

出　　处：《Journal of Central South University of Technology》2008年第5期684-688,共5页中南工业大学学报（英文版）

基　　金：Project(50675227) supported by the National Natural Science Foundation of China;Project(07JJ3091) supported by Natural Science Foundation of Hunan Province, China;Project(2007001) supported by the State Key Laboratory of Digital Manufacturing Equipment and Technology;Project(2009CB724203) supported by the Major State Basic Research Development Program of China

摘　　要：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.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 （〉5W） 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.

关 键 词：ultrasonic power wedge bonding thermosonic flip chip input impedance FAILURE 

分 类 号：O426[理学—声学]