热、振及热振耦合条件下塑封球栅阵列含铅焊点失效分析

PBGA solder joint fatigue under temperature cycling,random vibration and combined vibration and thermal cycling loading conditions

对塑封球栅阵列封装器件进行了热循环、随机振动以及热振耦合试验,在3种试验条件下测试Sn37Pb焊点的寿命,并对3种载荷条件下失效焊点位置的分布规律以及焊点的失效模式进行对比分析.结果表明,塑封球栅阵列封装焊点在热振耦合试验中的寿命明显小于热循环以及随机振动试验的寿命结果.热循环、随机振动条件下越靠近测试板中心位置,器件的焊点越容易发生破坏,而热振耦合试验中不同位置上器件的失效焊点数比较接近.此外,热循环条件下破坏模式主要表现为钎料内部的韧性断裂,随机振动条件下主要为界面金属间化合物层内的脆性断裂,而热振耦合条件下这两种破坏模式均有发生.

In this paper,temperature cycling,random vibration and combined loading tests were conducted on plastic ball grid array assemblies.The fatigue lives,the failure modes of the solder joints and the location of the failed solder joints for single loading and combined loading conditions were compared and analyzed.The results show much earlier solder joint failure for combined loading than that for either temperature cycling or pure vibration loading at room temperature.During temperature cycling and random vibration loading tests,the components at the central region have more failed solder joints than other components.The effect of the component location on the stresses and strains at the solder joints is not significant for combined loading.The primary failure mode is cracking within the bulk solder under temperature cycling,whereas the crack propagation path is along the intermetallic compound(IMC)layer for vibration loading.The solder joints subjected to combined loading exhibit both failure modes that occur for the temperature cycling and the vibration loading conditions.