电迁移致SnAgCu微焊点强度退化及尺寸效应研究

在100℃温度下,对直径为300μm、高度为100,200和300μm的Sn-3.0Ag-0.5Cu钎料微焊点施加密度为1×104A/cm2的直流电流。通电48h后,利用DMA对电迁移作用后微焊点拉伸强度的变化进行了研究。结果表明,电迁移作用导致微焊点拉伸强度明显退化,且退化程度随微焊点高度的减小而减弱。其中,高度为300μm的微焊点的平均拉伸强度由初始态的44.4MPa降至27.8MPa,下降了37.4%。电迁移还导致微焊点的断裂由延性变为延性与脆性相结合的模式。

Strength reduction of Sn-3.0Ag-0.5Cu solder joints caused by electromigration and the effects of joint size on strength reduction

Direct current with a density of 1×10~4 A/cm~2 was applied on three kinds of Sn-3.0Ag-0.5Cu micro solder joint at 100 ℃.These three kinds of solder joint have a same diameter of 300 μm but different heights of 100 μm, 200 μm and 300 μm.After 48 h, the effects of electromigration on the tensile strength of Sn-3.0Ag-0.5Cu solder joints were studied with DMA.The experimental results show that electromigration results in reduction in the tensile strength of solder joints and the reduction rate increases with increasing joint height.The average tensile strength of the joints with a height of 300 μm reduces from 44.4 MPa to 27.8 MPa after electromigration, with a reduction rate of 37.4%.While the control solder joints show brittle failure, both brittle failure and ductile failures are found for solder joints subject to electromigration.