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结合Sn-3.5Ag和Sn-3.0Ag-0.5Cu两种无铅钎料研究了镀镍浸金层(Electroless Nickel Immersion Gold,ENIG)表面层对焊点界面反应以及力学性能的影响。结果表明,钎焊后在Sn-3.5Ag/ENIG/Cu界面主要生成(Ni_yCu_(1-y))_3Sn_4,在Sn-3.0Ag-0.5Cu/ENIG/Cu界面主要生成(Cu_xNi_(1-x))_6Sn_5。在Sn基钎料/ENIG(Ni)/Cu界面处生成金属间化合物的种类及形貌由焊点中Cu原子含量决定。在时效过程中,ENIG表面层中Ni层有效抑制了焊点界面处金属间化合物的生长,减缓了焊点剪切性能的下降。在钎焊过程中ENIG表面层中的Au层不参与界面反应而是进入钎料基体与Sn反应,但是在时效过程中Au原子向界面迁移并造成焊点界面金属间化合物成分和焊点剪切强度的明显变化。
The effects of the surface layer of nickel-plated Immersion Gold (ENIG) on the interfacial reaction and the mechanical properties of the solder joints were investigated by using two lead-free solders, Sn-3.5Ag and Sn-3.0Ag-0.5Cu. The results show that (Ni_yCu_ (1-y)) _3Sn_4 is mainly formed at the interface of Sn-3.5Ag / ENIG / Cu after brazing and Cu_xNi_ (1-x) ) _6Sn_5. The type and morphology of intermetallic compounds generated at the Sn-based brazing material / ENIG (Ni) / Cu interface are determined by the Cu atom content in the solder joint. During the aging process, the Ni layer in the ENIG surface layer effectively suppressed the intermetallic compound growth at the solder joint interface and slowed the decline of the solder joint shear properties. In the brazing process, the Au layer in the ENIG surface layer does not participate in the interfacial reaction but enters the solder matrix and reacts with Sn, but during the aging process, the Au atoms migrate to the interface and cause the interfacial intermetallic compound component and the solder joint to be sheared Significant changes in intensity.