基于稳健设计的PBGA器件焊点热机械疲劳可靠性的优化设计

Optimal Design for Improving Thermo-Mechanical Fatigue Reliability of Solder Joint of PBGA Component Based on Robust Design

基于稳健设计与有限元法,研究了加速热循环测试条件下塑封球栅阵列（PBGA）焊点的热机械疲劳可靠性.考虑PCB大小（A）、基板厚度（D）、芯片热膨胀系数（G）、焊点热膨胀系数（H）等八个控制因素,使用L18（2^1×3^7）混合正交表,以对焊点热机械疲劳寿命的考核为目标,对PBGA焊点进行了优化设计.结果表明,影响焊点可靠性的显著性因素依次是基板热膨胀系数、焊点的热膨胀系数、基板厚度、芯片的热膨胀系数;最优方案组合为A182C3D1E2F1G3H1.进一步的验证试验结果表明,与原始方案相比,该优化方案的最大等效应变降低了66%,信噪比提高了22.4%.

Based on robust design and Finite Element Method,the thenno-mechanical fatigue reliability of PBGA（Plastic Ball Grid Array）solder joint subject to an accelerated thermal cycling test condition is studied.Including PCB size,substrate thickness,chip coefficient of thermal expansion（CTE）,and solder joint CTE et al.,8 different control factors are considered for a robust design towards enhancement of the thermal fatigue resistance of solder joint by using a L18（2^1×3^7）mixed-level orthogonal array. From the result,importance of these factors on the thermo-mechanical reliability of PBGA solder joint is ranked.The best parameter combinations is A1B2C3D1E2F1G3H1,which the substrate CTE,solder joint CTE,the thickness of substrate,die CTE are the most important.The optimal design,after further confirmative experiments,decreases the maximum equivalent strain by 66% and increases S/N by 22.4% compared to the original design.