铝质焊盘的键合工艺

Wire Bonding Process on Aluminum Pad

从铝质焊盘键合后易发生欠键合和过键合的故障现象着手,就铝焊盘上几种常见键合方式进行了探讨,得出键合的优先级为硅铝丝超声楔形键合、金丝热声球形键合、金丝热压楔形键合。对层状结构的焊盘在热声和热压键合的应力仿真对比分析,得出键合各因素的重要性排序为超声功率、键合压力、衬底加热温度和劈刀温度。通过正交试验设计,找到铝焊盘上较为适宜的键合方式及参数范围,可大幅减小铝焊盘键合后失铝现象的发生。同时,对于镀金小焊盘的键合,也可参考本方法来解决焊盘起层的问题。

Under bonding or over bonding are nominal phenomenon after wire bonding especially on Al bonding pads.several common bonding methods on aluminum solder pads were discussed,and the priority of bonding is determined to be Al-Si wire ultrasonic wedge bonding,thermo-sonic ball bonding with Au wire and thermo-compression wedge bonding with Au wire.By comparing and analyzing the stress simulation of layered structure solder pads in thermo-sonic bonding and thermo-compression bonding,it is concluded that the importance order of various bonding factors is ultrasonic power,bonding pressure,substrate heating temperature,and wedge heating temperature.By orthogonal experimental design,a suitable bonding method and parameter range can be found on Al pads,which can significantly reduce the occurrence of aluminum loss after bonding.At the same time,for the bonding of gold-plated small pads,this method can also be referred to solve the problem of pad delamination.