热冲击条件下1.27mm引脚间距塑封球栅阵列器件焊点可靠性测试与分析

Reliability test and analysis of 1.27mm pitch plastic ball grid array soldered joint under thermal shock

通过热冲击试验对1.27 mm引脚间距塑封球栅阵列(PBGA)器件焊点可靠性进行了测试与分析。选取钢网厚度、芯片配重、焊盘直径三个影响焊点可靠性的关键因素设计了多种不同工艺参数组合的PBGA测试样件,对样件进行了可靠性热冲击试验。对试验结果数据所进行的极差分析和方差分析以及对焊点寿命威布尔分布的计算表明,钢网厚度对PBGA焊点可靠性有显著的影响;最优工艺参数组合为钢网厚度0.15 mm、焊盘直径0.73 mm、芯片配重18.054 7 g;PBGA测试样件寿命服从形状参数为0.85,尺度参数为6 254.88的威布尔分布。

The soldered joint reliability of 1.27mm pitch plastic ball grid array (PBGA) package was studied by Taguchi design experiment method under the thermal shock. The stencil thickness, the pad diameter and the chip weight were chosen as the three critical factors for the design of the PBGA test specimens by using a Taguchi orthogonal array. The thermal shock cycling test of PBGA test specimens was carried out. The range analysis and the variance analysis were performed to determine both the best combination of the process parameters and the most influential factors; the failure distribution of PBGA soldered joints was also characterized by using two-parameter Weibull distribution. The results show that the thickness of stencil has a significant effect on the reliability of the 1.27 mm pitch PBGA soldered joints. The optimal of process parameters are the stencil thickness of 0.15 mm, the pad diameter of 0.73 mm and the chip weight of 18.0547 g. The failure life of PBGA soldered joint follows the two-parameter Weibull distribution, whose shape parameter and scale parameter are 0.85 and 6254.88, respectively.