Sn晶粒取向对微焊点元素迁移及界面反应的影响

Influences of Sn Grain Orientation on Element Migration and Interfacial Reaction in Micro Solder Joints

随着先进电子封装技术的不断发展,电子产品在服役时无铅微焊点内的元素迁移问题引起了广泛关注。由于先进封装互连尺寸的逐步缩小,微焊点扩散的各向异性问题日益凸显,即Sn晶粒取向显著影响元素的迁移行为,进而影响微焊点的界面反应。综述了在热时效、热循环、电流加载与温度梯度等条件下,Sn晶粒取向对焊点中元素迁移及界面反应的影响。现有研究结果表明,在热时效及热循环条件下,Sn晶粒取向对微焊点元素迁移及界面反应的影响较小,而Sn晶粒取向对微焊点的电迁移和热迁移有着相似的影响规律,并由此产生了界面金属间化合物(IMC)的非对称及非均匀生长现象。此外,还综述了基于数值模拟方法开展的微焊点元素扩散各向异性的相关研究,并对不同条件下的研究进展进行了总结。

With the continuous development of advanced electronic packaging technology,the element migration within lead-free micro solder joints in service of electronic products has attracted a lot of attentions.As the interconnections for advanced packaging are gradually downsizing,diffusion anisotropy has become an increasingly prominent issue for micro solder joints.That is,Sn grain orientation significantly affects the element migration behavior,which affects the interfacial response of the micro solder joints.The influences of Sn grain orientation on element migration and interfacial reactions in micro solder joints under thermal aging,thermal cycling,current loading and temperature gradient are reviewed.It has been found that Sn grain orientation has little effect on element migration and interfacial reactions of micro solder joints under thermal aging or thermal cycling,while Sn grain orientation has a similar effect on electromigration and thermomigration behavior,resulting in the asymmetrical and uneven growth of interfacial intermetallic compounds(IMCs).In addition,studies on the anisotropy of element diffusion in micros solder joints based on numerical simulation methods are also reviewed,and the progress of the studies under different conditions is summarized.