研究Cu/Sn/Ni焊点在250℃液一固界面反应过程中Cu—Ni交互作用对界面反应的影响。结果表明:液一固界面反应10min后,Cu-Ni交互作用就已经发生,Sn/Cu及Sn/Ni界面金属问化合物(IMCs)由浸焊后的cu6sn5和Ni3Sn4均转变为(Cu,Ni)6Sn5,界面IMCs形貌也由扇贝状转变为短棒状。在随后的液一固界面反应过程中,两界面IMCs均保持为(Cu,Ni)6Sn5类型,但随着反应的进行,界面IMC的形貌变得更加凸凹不平。Sn/Cu和Sn/Ni界面IMCs厚度均随液一固界面反应时间的延长不断增加,界面IMCs生长指数分别为0.32和0.61。在液一固界面反应初始阶段,SrdCu界面IMC的厚度大于Sn/Ni界面IMC的厚度;液一固界面反应2h后,由于Cu.Ni交互作用,Sn/Cu界面IMC的厚度要小于Sn/Ni界面IMC的厚度,并在液一固界面反应6h后分别达到15.78和23.44μm。
The effect of Cu-Ni cross-solder interaction on liquid-solid interfacial reaction in Cu/Sn/Ni solder joint at 250 ℃ was investigated. The results show that the Cu-Ni cross-solder interaction occurs after liquid-solid reaction for 10 rain, the initial Cu6Sn5 and Ni3Sn4 form during immersing soldering at the Sn/Cu and Sn/Ni interfaces, and both transform into (Cu,Ni)6Sns, their morphologies change from scallop shape to rod shape. With increasing reaction time, the interfacial IMCs remain as (Cu,Ni)6Sns, while their morphologies become more uneven. The IMCs at the Sn/Cu and Sn/Ni interfaces grow thicker with increasing reaction time, and their growth indexes are 0.32 and 0.61, respectively. At the beginning of the liquid-solid reaction, the Sn/Cu interfacial IMC is thicker than the Sn/Ni interfacial IMC. However, after liquid-solid reaction for 2 h, the result reverses due to the Cu-Ni cross-solder interaction, and the thicknesses reach 15.78 and 23.44 μm after reaction for 6 h, respectively.