温度冲击下IGBT高铅焊料层的组织演变与裂纹扩展

Microstructure evolution and crack propagation of IGBT high lead solder layer under temperature shock

采用三种高铅焊料(Pb90Sn10,Pb92.5Sn5Ag2.5,Pb95.5Sn2Ag2.5)连接绝缘栅双极晶体管(IGBT)芯片与Cu框架,分析了温度冲击下焊料层组织的演变与裂纹的扩展.研究结果发现:焊料界面上的金属间化合物随着温度冲击次数的增加而增加;Ag3Sn向焊料基体的移动产生应力集中,降低了焊料的可靠性;在250次温度冲击后焊料内出现裂纹,裂纹从焊料层与芯片界面的边角萌生,并沿界面向焊料层中心扩展;Pb95.5Sn2Ag2.5的抗裂能力最高,Pb92.5Sn5Ag2.5次之,Pb90Sn10最差;该结果可为绝缘栅双极晶体管器件的疲劳可靠性研究提供支撑.

Three kinds of high lead solder(Pb90Sn10,Pb92.5Sn5Ag2.5,Pb95.5Sn2Ag2.5)were used to connect insulated gate bipolar transistor(IGBT)chip to copper frame,and the microstructure evolution and crack propagation of the solder layer under temperature impact were studied.Research results show that the intermetallic compounds on the solder interface increase with the increase of temperature shock times.The movement of Ag3Sn to solder matrix results in stress concentration,which reduces the reliability of solder.The cracks appear in the solder after 250 temperature shocks.The cracks start from the edge of the interface between the solder layer and the chip,and spread along the boundary towards the center of the solder layer.The crack resistance of Pb95.5Sn2Ag2.5 is the highest,followed by Pb92.5Sn5Ag2.5,and Pb90Sn10 is the worst.The results can provide support for the fatigue reliability research of IGBT devices.