回流焊工艺中PBGA焊点失效研究

Investigation of PBGA Solder Joint Failure in Reflow Process

在PGBA封装中,焊点不仅提供机械支撑、电传导和热传导等作用,同时承受着电子设备的高温运行中,频繁的受热、机械、电载荷作用。因此,考虑到焊点质量直接关系到PGBA产品在实际应用中的可靠性,采用有限元方法研究了PBGA焊点在回流焊工艺中热应力、应变的分布规律,确定最大应力、应变位置,进而预测PBGA焊点结构失效危险点。结果表明,PBGA焊点最大应力、应变均出现在焊点与BGA、PCB连接面拐角位置,由此可知,PBGA拐角处焊点为结构失效危险点。

In PBGA package,solder joint provides not only mechanical support,electrical conduction and thermal conduction effect,but also withstands frequent thermal,mechanical,electrical loads in the high temperature operation of the electronic device. Thus,solder joint quality is directly related to PGBA products reliability in the practical application. Based on the finite element method,the thesis studies the thermal stress and strain distribution of PBGA solder joint during the reflow process so as to locate the maximum stress and strain. Furthermore,dangerous solder joint of PBGA failure is predicted as well. Studies show that the maximum stress and strain of solder joint are present in the corner joints between BGA and PCB connection surface. From this point of view,the danger joints of structural failure are the corner solder joints of PBGA.