界面Ni_(3)Sn_(4)微观形貌演变对微焊点力学性能的影响

Effect of interfacial Ni_(3)Sn_(4) micro morphology evolution on mechanical properties of micro solder joints

针对Ni/(20μm)Sn/Ni微焊点,研究界面金属间化合物(IMC)Ni_(3)Sn_(4)微观形貌演变及其对微焊点力学性能的影响,并对拉伸断口进行分析。结果表明,随着回流时间增加,Ni_(3)Sn_(4) IMC厚度快速增加,其形貌也发生显著变化,由短棒状转变成长棒状,最后演变成块状;微焊点的抗拉强度表现为先减小、再持续增大的反常变化趋势,界面Ni_(3)Sn_(4)微观形貌演变成为主导因素,转变成长棒状的Ni_(3)Sn_(4)引起应力集中,造成微焊点的强度降低,继续转变成的块状Ni_(3)Sn_(4)增加了裂纹抗力,提高了抗拉强度。微焊点的断口形貌进一步证实了Ni_(3)Sn_(4)微观形貌演变对微焊点力学性能影响。

For Ni/(20μm)The microstructure evolution of interfacial intermetallic compound(IMC)Ni_(3)Sn_(4) and its effect on the mechanical properties of Sn/Ni micro solder joints were studied,and the tensile fracture was analyzed.The results showed that with the increase of reflux time,the thickness of Ni_(3)Sn_(4) IMC increased rapidly,and its morphology also changed significantly,from short rod to long rod,and finally to block.The tensile strength of micro solder joints showed an abnormal trend of decreasing first and then increasing continuously.The micro morphology of interface Ni_(3)Sn_(4) had evolved into the dominant factor.The transformation of long rod Ni_(3)Sn_(4) caused stress concentration and reduced the strength of micro solder joints.The continuous transformation of massive Ni_(3)Sn_(4) increased the crack resistance and improved the tensile strength.The fracture morphology of micro solder joints further confirmed the influence of Ni_(3)Sn_(4) micro morphology evolution on the mechanical properties of micro solder joints.