SnCu钎料镀层与Cu/Ni镀层钎焊接头的界面反应

Interfacial reactions between Sn-Cu solder alloy and Cu/Ni coatings during reflow soldering

观察了不同焊接工艺条件下钎焊接头界面的微观结构,并对钎焊过程中的界面反应进行分析。探讨了钎缝界面处IMC的生长机制,通过对不同钎焊温度和保温时间下的IMC生长规律的分析建立铜锡化合物厚度与温度和时间的关系方程。结果表明:钎焊过程中SnCu钎料合金镀层与可焊性Cu层的界面处生成金属间化合物Cu6Sn5和Cu3Sn;化合物的生长厚度与焊接时间之间满足抛物线关系,表明化合物的生长为扩散反应控制过程,并随焊接时间的延长化合物的生长速率逐渐下降。

The interface microstructures of soldered joints under different soldering techniques were observed and analyzed. The interface reaction during soldering was studied. The growth mechanism of the IMCs was discussed and the influences of soldering temperature and dwell time on IMC evolution were investigated. The equation of the relationship between IMCs thickness and soldering conditions including soldering temperature and dwell time was developed. The results suggest that, during soldering, the joint interface between the solder and Cu/Ni coating exhibits a duplex structure of Cu6Sn5 and Cu3Sn intermetallic compounds （IMCs）. A parabolic relationship exists between the growth of the IMC layer and soldering time. This indicates that the mechanism of IMC growth is a diffusion-controlled process. The growth rates for the intermetallic layers increase with soldering temperature, whereas decreases with time.