无氰共沉积Au-Sn共晶合金薄膜

Cyanide-free Co-deposition of Au-Sn eutectic alloy film

电化学沉积是一种制备高性能与高可靠Au-30%(原子分数)Sn共晶合金封装材料的较好方法。采用恒电流法从一种无氰Au-Sn电镀液中沉积得到Au-Sn共晶合金薄膜。通过电化学测试、合金薄膜成分与形貌分析以及多批次重现性实验,确定在-2.0 mA/cm^(2)电流密度下可以沉积出表面平整致密且Sn原子含量稳定在30%(原子分数)左右的Au-Sn共晶合金薄膜。Au-Sn共晶合金薄膜的沉积速率约为5.0μm/h。差热分析曲线(DSC)表明,Au-Sn共晶合金薄膜共晶点温度为277.4℃,与理论值相一致。另外,该无氰Au-Sn电镀液具有较好的储存寿命。研究结果可以为无氰共沉积Au-Sn共晶合金薄膜提供一定的参考和经验。

Electrochemical deposition is a good method to prepare high-performance and highly reliable Au-30 at% Sn eutectic alloy packaging materials.A galvanostatic method was used to deposit Au-Sn eutectic alloy film from a cyanide-free Au-Sn electroplating bath.Through electrochemical testing,composition and morphology analysis,and multiple batch reproducibility experiments,it was determined that Au-Sn eutectic alloy film with a smooth and dense surface and a Sn content of about 30 at% could be deposited at a current density of-2.0 mA/cm^(2).The deposition rate of Au-Sn eutectic alloy film was about 5.0μm/h.The differential thermal analysis curve(DSC)showed that the eutectic point temperature of the Au-Sn eutectic alloy film was 277.4℃,which was consistent with the theoretical value.In addition,the cyanide-free Au-Sn electroplating solution had a good shelf life.The results could provide certain reference and experience for the non-cyanide co-deposition of Au-Sn eutectic alloy films.