IGBT模块超声检测缺陷判据研究

Research on Criterion of Defects Inspected by Ultrasonic Scanning in IGBT Module

焊层缺陷是影响功率模块寿命和可靠性的主要因素之一,主要采用有限元仿真的研究方法,模拟了焊层缺陷位置、大小等因素对IGBT模块热性能的影响,得到不同的缺陷情况与模块热性能的对应关系并进行拟合,计算出焊层空洞大小临界值,提出了一种IGBT模块超声检测缺陷判据标准。芯片-基板焊层单个空洞率需≤2%,基板-底板焊层单个空洞率需≤2%,芯片-基板焊层整体空洞率与基板-底板焊层整体空洞率之和需≤10%。

Solder joint defect is one of the key factors relating to the lifetime and reliability of power module. The affecting factors to thermal performance of IGBT module,such as location and size of solder joint defects,were studied by finite element analysis(FEA)method. The correspondence and fitting relationships between thermal performance and solder joint defects were revealed,and the critical value of solder layer void ratio was calculated. A criterion of defects inspected by ultrasonic scanning in IGBT module was presented. The single void ratio of die-substrate solder layer should be no more than 2%,as well as the single void ratio of substrate-base plate solder layer. The sum of total void ratio of the solder layers mentioned above should be less than or equal to 10%.