【摘要】 采用球栅阵列封装（BGA）焊点研究共晶SnPb焊点中的电迁移行为,分析了电迁移作用下SnPb焊点与Ni（P）镀层界面金属间化合物（IMC）的极性生长现象,从原子迁移的角度提出了互连焊点微结构演化的微观机理.焊点在焊接过程中形成厚度约为2μm的Ni₃Sn₄ IMC层,随后的120℃热处理并不会导致界面IMC的明显生长.而电迁移作用下,阳极焊点与镀层界面IMC出现异常生长,同时阴极焊点与镀层界面IMC生长受到抑制,最终在同一焊点中形成极性生长的现象.界面IMC的极性生长与电迁移引起的原子通量有关,Sn原子通量方向与电子流方向相同,而Ni原子通量方向相反,导致阳极界面IMC的异常生长,而相同的原子迁移特性导致阴极界面IMC的生长受到抑制.更多还原

【Abstract】 The polarity growth of intermetallic compound（IMC）at the interface between eutectic SnPb BGA solder joints and Ni（P）finishes was investigated and the mechanism of microstructural evaluation was explained by the migration of atoms in interconnects.Ni₃Sn₄ IMC layer of 2μm in thickness was formed during the soldering reaction and the subsequent annealing at 120℃can not induce the visible growth of IMC.The IMC layer shows abnormal growth at the anode interface,while the growth at the cathode interface is restrained.Finally,the upper-side and lower-side interfaces of the same solder joints show polarity effect on the growth of IMC.The polarity effect is related with the flux of atoms in interconnects.The direction of electron flow is consistent with the flux of Sn atoms, while opposite to the flux of Ni atoms.The flux of atoms induced the abnormal growth of IMC at the anode interface but restrained the growth at cathode interface.更多还原