交变电磁辐射下SnPb共晶钎料在BGA焊盘上的自发热重熔及界面反应

进行了交变电磁辐射下附Au／Ni镀层BGA焊盘上SnPb共晶钎料球感应自发热重熔形成钎料凸台的实验，并分析了感应自发热重熔以及固态老化对SnPb共晶钎料与Au／Ni镀层焊盘界面反应的影响．研究结果表明，交变电磁辐射一次重熔与红外重熔结果一样使Au镀层完全消失，并在钎料中形成离散的针状AuSn4，但是二次重熔结果由于电磁场作用下液体金属内固态金属颗粒聚集效应作用的结果使AuSn4金属间化合物富集在钎料与焊盘的界面处．固态老化过程中针状AuSn4转化为层状(AuxNi1-x)Sn4并粘着在Ni3Sn4上，抑制Ni3Sn4的长大。

Self Excite Reflowing and Interfacial Reaction of SnPb Eutectic Solder on BGA Pad Under Alternate Electromagnetic Radiation

SnPb eutectic solder reflow on BGA pad metallized with Au/Ni to form solder bump with induction self excite heat under alternate electromagnetic radiation is performed, and impacts of induction self excite heat and solid state aging on interfacial reaction between SnPb eutectic solder and Au/Ni metallization are investigated. Experimental results show that Au layer disappeared completely from metallization layer under first reflow by alternate electromagnetic radiation and formed needle shape AuSn4 scattered in SnPb eutectic solder, it is the same as that re-flowed by infrared heat. Under second reflow by alternate electromagnetic radiation the AuSn4 is concentrated at interface between the solder and the pad due to effect of solid metal granule conglomeration in liquid metal under electromagnetic field. The needle shape AuSn4 is evolved into layer shape (AuxNi1-x)Sn4 during solid state aging, it restrains growth of Ni3Sn4 at the interface.