Viration Transfer Process at Thermosonic

Flip Chip Bond Interface

WANG Fuliang  LI Junhui  HAN Lei  ZHONG Jue

(School of Mechanical and Electronical Engineering, Central South University, Changsha 410083)

Abstract: A laser Doppler vibration (LDV) measurement system was setup to monitor the real time vibration of bonding tool and flip chip in thermosonic flip chip bonding. By analyzing the vibration of chip and comparing with the vibration of tool tip, the “stall” phenomena of chip is elucidate, which is significant critical phenomena indicating bonding states changing during bonding process. Stall means that the initial bonding strength is formed at the bonding interface. The chip was vibrated with tool tip before “stall”. After “stall”, relative movement produced between them, a part of tool energy is propagated to the bonding interface via chip and formed bonding strength, and a part of energy is consumed at the tool/chip interface friction, which caused damage to bonding strength and bonding interface structure, caused damage on the surface of chip and tool. Finally, a novel bonding parameter apply method is developed to reduce the friction and to enhance the bonding strength.

Key words: Thermosonic flip chip bonding  Vibration transfer  Vibration monitoring Laser  Doppler vibration measurement

CLC No: TN911.6 TG453+.9

国家重点基础研究发展计划(973计划，2003CB716202)、国家自然科学基金(50705098)资助项目. Received 20070312, received in revised form 20070917