热超声倒装键合中换能杆末端多维振动的相关性研究

换能杆末端的振动情况对于超声键合机理的研究有着重要意义；换能杆末端的实际振动模式直接影响着芯片键合的质量。利用高精度非接触式激光多普勒测振仪采集了换能杆末端俯仰、水平、轴向振动速度，用相干函数方法分析了3个方向的相互耦合关系。分别对换能杆末端有未安装劈刀的情况做了比较，得出了在换能系统工作频率附近，换能杆末端轴向振速与水平、俯仰振速的相关程度。这对实际键合中，换能系统末端的劈刀安装长度的选择以及换能杆工作频率的选择有指导意义。

Experimental study of multi-dimensional vibration of transducer tip in an ultrasonic bonding system

Vibration at the end of the transducer affects the quality of ultrasonic flip chip bonding directly. The investigations to that vibration are therefore of great significance for understanding of Thermo-Ultrasonic Flip Chip process. With the experimental data acquired by laser Doppler Vibrameter, this paper analyses the vibration coupling along the pitching, horizontal and axial directions from the coherence function point of view. All the work can be classified into two stages according to the capillary on/off. The axial and horizontal rate of contribution to the pitching direction has been drawn near the transducer working frequency. This work can be guidance of selection for the length of the capillary and the working frequency of the transducer.