BGA混合焊点热循环负载下的可靠性研究

焊料从有铅向无铅转换中,不可避免会遇到二者混合使用的情况,有必要对生成的混合焊点进行可靠性研究。通过对不同工艺参数下形成的混合焊点和无铅焊点进行了外观检测、X射线检测和温度循环测试。结果显示,只要工艺参数控制得当,混合焊点是可行的。在焊球合金、焊料合金、峰值温度、液相线以上时间和焊接环境五个关键因素中,前四项对焊点可靠性比较重要,焊接环境对焊点可靠性的影响不很显著。

Reliability study of BGA mixed solder joint under thermal cycle

In the transition,solder from lead to lead-free,there is expected to be a period when the lead and lead-free will be mixed used,so it is necessary to study the reliability of the mixed solder joints.Through appearance testing,X-Ray testing and temperature cycling testing,the reliability of mixed solder joints and lead-free solder joints which formed under various process parameters was assesed.The results show that the mixed solder joints are feasible when the process parameters are controlled properly.In the five key factors of solder ball alloy,solder paste alloy,peak temperature,the time above liquidus and soldering environment,the fore four factors are more important than soldering environment to the solder joints reliability.