钎焊及时效过程中化学镀Ni-P与Sn-3.5Ag的界面反应

Interfacial reactions between Sn-3.5Ag solder and electroless Ni-P during soldering and aging

研究磷含量为6.5%(质量分数)的化学镀Ni-P薄膜与Sn-3.5Ag钎料合金之间的润湿行为,以及Sn-3.5Ag/Ni-P焊点在钎焊和时效过程中的界面反应。结果表明:250℃时,直径为(2.3±0.06)mm的Sn-3.5Ag焊球在化学镀Ni-6.5%P薄膜上钎焊后得到的润湿角约为44,铺展率约为67%;焊点界面由Ni3Sn4IMC层、及较薄的Ni-Sn-P过渡层构成Ni3P晶化层;钎焊过程中界面Ni3Sn4IMC的生长速率与钎焊时间t1/3呈线性关系;时效过程中界面Ni3Sn4IMC及富P层的生长速率与时效时间t1/2呈线性关系。

The wetting behavior of Sn-3.5Ag solder on the electroless Ni-P film with 6.5%P（mass fraction） during soldering and the interfacial reactions between Sn-3.5Ag solder and electroless Ni-6.5%P during soldering and aging were investigated.The results show that the wetting angle is about 44 and the spreading coefficient is about 67%using the solder balls with diameter of（2.3±0.06） mm at 25℃.The soldering interface are composed of a Ni3Sn4 IMC layer,a thinner Ni-Sn-P layer and a Ni3P crystallization layer between Sn-3.5Ag solder and electroless Ni-P.The growth kinetics of the interfacial IMC Ni3Sn4 during soldering follows a linear relation with cubic root of soldering time.The growth kinetics of interfacial IMC Ni3Sn4 and P-enriched layer during aging obeys a linear relation with square root of aging time.