전자부품 커넥터의 접속 신뢰성 향상을 위한 Au-Sn 합금 도금층 연구

A study on Au-Sn alloy plating layer improving reliability of electrical contacts

In this study, the effect of Au-Sn alloy coating on reliability of electrical contacts was investigated via comparison with Au-Co alloy coating. The results show that Au-Sn alloy exhibited lower contact resistance and higher solder spreadability than those of Au-Co alloy after thermal aging. In the case of Au-Co alloy plating, the underlying Ni element diffused into Au-Co layer to form Ni oxides on surface during thermal aging, leading to increased contact resistance and decreased solder spreadability. Meanwhile, for Au-Sn alloy plating, Au-Ni-Sn metallic compound was formed at the interface between Au-Sn layer and underlying Ni layer. This compound acted as a diffusion barrier, thereby inhibiting the diffusion of Ni to Au-Sn layer during thermal aging. Consequently, Au-Sn alloy layer showed better contact reliability than that of Au-Co alloy layer.