Al焊盘表面氧化膜对金丝键合的影响

Influences of Surface Oxide Films of Aluminum Bondpads on Gold Wire Bonding

摘要:

在半导体制造工艺中，Al焊盘表面的氧化膜会阻碍金丝键合。针对某公司新半导体工艺中出现键合失效问题的芯片，采用SEM，EDS和AES对切片前后的芯片进行了分析，结果发现，切片前后Al焊盘表面的元素成分基本一致。可以认为清洗工艺对金丝键合基本没有影响，它不是导致金丝键合失效的原因；通过AES对焊盘进行深度剖析，在深度接近Al焊盘高度的一半时，氧的含量仍然高达40%左右，如此高含量的氧已经足以将Al完全氧化，其所形成的氧化膜阻碍了金丝键合所必需的金属连接和扩散过程，从而导致键合质量差，甚至无法实现键合。

Abstract:

During semiconductor manufacturing, the gold wire bonding is influenced by the native Al oxide film, and Au wire could not bond to Al bondpad.In this paper, SEM, EDS and AES are used to investigate the bondpads. It's found that the elements on the surface of Al bondpads after sawing are consistent with those of before sawing. So swilling techniques does not affect the wire bonding. The AES results show that there is 40% O element in Al bondpads even though at the depth of half of the Al bondpad height. Consequently, Al has already been oxidized by O. The Al oxide film which can prevent the bonding and the diffusion of O to Al causes the failure of wire bonding.