SAC0307-xNi/Ni焊点的IMC及镍镀层的消耗

IMC of SAC0307-xNi/Ni soldered joint and consumption of Ni coating

关键词:  SAC0307-xNi  钎料  镍盘  金属间化合物  老化

Key words:  SAC0307-xNi  solder  Ni substrate  IMC  aging

摘要:

利用扫描电镜(SEM)对焊点SAC0307/Ni(Sn-0.3Ag-0.7Cu/Ni)和SAC0307-0.05Ni/Ni(Sn-0.3Ag-0.7Cu-0.05 Ni/Ni)经过180℃老化后的界面金属间化合物(IMC)的微观结构及镍镀层的消耗进行了研究.结果表明,回流焊后,SAC0307/Ni和SAC0307-0.05Ni/Ni焊点的IMC层均为(Cu_1-xNi_x)₆Sn₅,且随着老化时间的延长,IMC层的厚度均逐渐增加,化合物类型没有变化,但IMC的化学组成有所改变.SAC0307-0.05Ni/Ni焊点中IMC层形貌为蠕虫状,厚度比不加镍时有所降低.回流焊后两种钎料焊盘的镍层消耗几乎相同,但老化384 h后SAC0307/Ni的焊盘镍层的剩余厚度明显比SAC0307-0.05Ni/Ni的小.因此,钎料中添加适量的镍可以有效地降低焊盘镍层在时效过程中的消耗速率,即显著提高镍焊盘的抗老化能力.

Abstract:

The microstructure of interfacial IMC and the consumption of Ni layer for SAC0307/Ni(Sn-0.3Ag-0.7Cu/Ni) soldered joint and SAC0307-0.05Ni/Ni(Sn0.3Ag-0.7Cu-0.05Ni/Ni) soldered joint after aging at 180℃ were studied by scanning electron microscope(SEM).The results indicated that the IMC layer of SAC0307/Ni and SAC0307-0.05Ni/Ni are both(Cu_1-xNi_x)₆Sn₅ after reflow soldering.With the increasing of aging time, the thickness of IMC layer increases gradually, the type of IMC is not changed, but the chemical composition changes.The morphology of IMC is storm-shaped and the thickness of IMC is much thinner when SAC0307 solder added 0.05% Ni is used.The consumption of Ni layer is nearly the same using both solders after the first time reflow soldering, but the residual thickness of the Ni layer in SAC0307/Ni solder is thinner than that in SAC0307-0.05Ni/Ni after aging for 384 h.So solders with a little Ni element can decrease the consumption rate of Ni layer effectively during aging, that is, the aging-resistant ability of Ni pad is improved obviously.