层间粘接剂对刚挠板通孔可靠性的影响分析

在刚挠结合印制板中,层间不同粘接材料的热性能与镀层差异较大时,在热循环的条件下孔内镀层会发生疲劳断裂从而导致电性能缺陷。以两种典型的层间材料(不流动半固化片和纯胶片)为例,对影响PTH孔铜可靠性的材料特性因素方面进行探讨,首先采用一定的通孔应力应变模型理论分析通孔的应力分布,进而结合通孔的失效评估模型理论计算了不同材料下不同孔径的通孔的疲劳寿命,确定了不同介质材料下通孔的耐热循环性能;最后,通过冷热循环试验进行验证,对比出两种层间材料的差异,同时,通过对失效板件进行切片及SEM形貌分析,提出了PTH在热冲击下的失效原因和机理,获得了材料选择和性能对比的依据。

Impact of adhesive on reliability of PTH in rigid-flex PCB

The thermal characteristic of difference materials between a rigid-flex PCB has great impacts on the reliability of PTH;the PTH copper would be crack under periodic thermal stress condition.This paper discuss different effects of material which affect the PTH reliability,first some stress-strain model was adopted to calculate the PTH stress,and then the fatigue life of PTH was predicted by IPC reliability evaluate model.The performance of different materials and hole diameter was confirmed.Lastly,thermal sh...