夹持环对换能系统振动模态影响的有限元分析

换能系统是热超声引线键合装备的核心部分,夹持环对系统起安装支撑的作用,其安装方式直接影响换能系统的能量传递与振动模态。利用有限元法分析了夹持环对换能系统振动模态的影响,结果表明,对夹持环未施加约束、施加z向约束时换能系统的夹持环会出现振动现象,而施加x向约束时,工作频率下的主振型完全不符合要求;改变夹持环的安装位置,对换能系统的节点位置及谐振频率都有一定的影响,实验测得在全约束情况下,换能系统的节点位置为58 mm,与分析结果一致;换能系统在工作频率附近包含有其他的振动模态,在键合过程中易被激发出来,由此消耗超声能量而降低芯片的键合质量,这些振动模态必须得到抑制。

Finite Element Analysis of the Influence of the Retainer Ring on the Vibration Modal in Transducer System

The transducer system is a key component of the bonding equipment in the thermosonic bonding system.Retainer ring sustains the transducer system,and the mode of mounting affects the energy delivery and the vibration modal of the transducer system directly.Finite element analysis is applied to analyze the influence of the retainer ring on the vibration modal in transducer system,the consequence shows that the retainer ring will be vibratory when it is restrained by z direction or when it is free;the principal mode in the working frequency is not consistent accord with the requirement when it is restrained by x direction;and the node position and the harmonic frequency will be affected when the mounting position of the retainer ring is changed,the experiments indicate that the node position of the transducer system is 58 mm when the retainer ring is restrained all,and it is consistent with the finite element analysis;There are many other undesirable modes that may be excited because they are very close to working frequency.Since these undesirable modes would waste ultrasonic energy and badly influence on bonding quality between gold ball and substrate,they should be well controlled in bonding.