Anand’s visco-plasticity model was used to describe mechanical property of lead-free solders SAC305 under temperature cycle load. Finite element method was employed in the analysis of the stress and strain response of lead-free solders (SAC305) in plastic ball grid array package, especially the strain energy of key solders was discussed. The results show that the critical region appears on the surface edge of the most critical solder joints, where fatigue damage often initiates and propagates, which is verified by experiment. Plastic strain rate in temperature rising is much higher than that in high temperature lingering in temperature cycle, which affects the fatigue life of solder joints vastly.%采用 Anand 模型描述无铅焊点（SAC305）的力学性能，运用有限元法模拟球栅阵列封装在温度循环载荷下的应力应变响应并对其进行分析，着重对关键焊点的应变能进行了讨论。结果表明，关键焊点的关键区域出现在焊点的上表面边缘处，为最容易出现损坏的部位，并得到了实验的验证；在温度循环的过程中，升温阶段塑性应变产生速率远高于高温驻留阶段的塑性应变产生速率，极大地影响着焊点使用寿命。
展开▼
