感应自加热重熔无铅焊料凸台的剪切失效模式

通过两次高频感应重熔制备了Cu焊盘上S n3．5Ag焊料和Sn3．0Ag0．5Cu焊料凸台,并进行了120℃下的老化试验以及老化试件的剪切强度试验,分析了不同老化时间下两种无铅焊料凸台的剪切断裂模式。焊料凸台的剪切载荷-位移曲线的特征以及对焊料凸台剪切断口的扫描电镜形貌分析结果表明,不同老化时间下无铅焊料凸台的剪切断裂表现为塑性、韧性和脆性三种断裂模式。对凸台焊料合金的组织以及界面观察结果表明,随老化时间不断生长的脆性金属间化合物层以及焊料组织粗大是致使断裂失效模式转变的根本原因。

Shear Fracture Model of Lead-free Solder Bump Formed with Induction Self Heat Reflow

The shear failure modes and respective failure mechanism of Sn3.5Ag and Sn3.0Ag0.5Cu lead-free solder bumps on Au/Ni/Cu pad metallization formed by twice Induction Self Heat Reflow processes have been investigated in the shear test after aging 0,1,4,9,16 days at 120℃.The character of loading curves(shear force vs.displacement)has shown three different typical shear failure behaviors.From the result of interfacial morphology analysis of the fracture surfaces and cross-sections,three typical failure modes:brittle,tough and ductile,have been identified.The probability of three failure modes occurrence with different aging time is different.The evolution of the brittle IMC Ni_3Sn_4 and Cu-Ni-Au-Sn IMC layers and the grains coarsening of solder bulk are the basic reasons for the change of shear failure modes.