Cu­Ni 交互作用对 Cu/Sn/Ni 焊点液-固界面反应的影响

摘要

The effect of Cu­Ni cross­solder interaction on liquid­solid interfacial reaction in Cu/Sn/Ni solder joint at 250℃ was investigated. The results show that the Cu­Ni cross­solder interaction occurs after liquid­solid reaction for 10 min, the initial Cu6Sn5 and Ni3Sn4 form during immersing soldering at the Sn/Cu and Sn/Ni interfaces, and both transform into (Cu,Ni)6Sn5, their morphologies change from scallop shape to rod shape. With increasing reaction time, the interfacial IMCs remain as (Cu,Ni)6Sn5, 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 liquid­solid reaction, the Sn/Cu interfacial IMC is thicker than the Sn/Ni interfacial IMC. However, after liquid­solid reaction for 2 h, the result reverses due to the Cu­Ni cross­solder interaction, and the thicknesses reach 15.78 and 23.44 μm after reaction for 6 h, respectively.%　　研究 Cu/Sn/Ni 焊点在250℃液−固界面反应过程中 Cu­Ni 交互作用对界面反应的影响。结果表明：液−固界面反应10 min 后，Cu­Ni 交互作用就已经发生，Sn/Cu 及 Sn/Ni 界面金属间化合物(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−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−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−固界面反应初始阶段，Sn/Cu 界面 IMC 的厚度大于 Sn/Ni 界面 IMC 的厚度；液−固界面反应2 h 后，由于 Cu­Ni 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−固界面反应6 h 后分别达到15.78和23.44μm。