PCBA漏电、短路失效分析 --美信检测 失效分析实验室¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR摘要：¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
本文通过无损及结构分析，发现样品失效根本原因是PCB板存在质量异常，部分产品出现了内部铜线异常搭接于焊盘位置。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR.jpg)
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR关键词：¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR PCB、PCBA、漏电、短路¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR1.案例背景¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR PCBA使用过程中发现存在漏电、短路现象。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR2.分析方法简述¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR 通过外观检查，未发现PCB及PCBA样品短路线路上有任何外观不良。在进行电阻测试排查的过程中，发现在PCBA板在A区域的电容与其下方电阻之间存在短路。PCB板样品中未发现异常。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR X-Ray透视发现PCBA样品在A区域均可看到内部框架的金属细丝连接到电容的一个电极，该异常现象在委托方提供的失效样品中均存在。PCB板中发现了一个样品存在有金属丝接近该焊盘但未连接。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR.jpg)
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
通过去除失效样品表面绿油，可明显看到PCBA样品该位置铜皮连接到A区域电容电极。PCB样品A区域铜丝连接电容焊盘的连接点有明显过电的痕迹。通过对失效样品水平研磨观察，明显可看到该异常铜皮与是与其相邻铜焊盘连接。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR.jpg)
3.结果与讨论¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
根据以上的测试结果，可以明显的看出导致PCBA样品失效不是因为其焊接不良引起的短路。焊接工艺也不会导致PCBA样品出现绿油下的铜丝在绿油不破损的情况下产生形变搭接在相邻的元件焊盘位置。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
去绿油后，可以明显的看到，X-Ray所看到的铜线直接连接到了A区域的焊盘，对比正常PCB板的A区域，该铜线应该平行存在于两焊盘中间位置。但从目前我们看到的现象可知，失效PCBA板的该位置铜线均出现了偏移，不均匀的搭接于电容焊盘上。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
因此，可判定导致PCBA失效的原因为PCB板存在质量异常，部分产品出现了内部铜线异常搭接于焊盘位置。因而致使相关电路出现了漏电、短路现象。¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
¬²ÉWìÊÇbbs.3c3t.comjx¬µãR
%20(2)_1.gif)
