Non-destructive imaging of defects in Ag-sinter die attach layers - A comparative study including X-ray, Scanning Acoustic Microscopy and Thermography
Non-destructive imaging of defects in Ag-sinter die attach layers - A comparative study including X-ray, Scanning Acoustic Microscopy and Thermography
复制标题
DOI：
10.1016/j.microrel.2018.07.121
复制
发表时间：
2018-09-01
影响因子：
1.6
通讯作者：
Brabec, C. J.
中科院分区：
文献类型：
--
作者：
Dreher, P.;Schmidt, R.;Brabec, C. J.
在典型的电力电子模块中，几个半导体管芯（诸如MOSFET或IGBT）被焊接到DBC基板。在模块生产过程中，可以通过使用X射线检查来监控焊料层的质量，并可以确定空隙率。最近，更强大的银烧结技术被部署用于将功率管芯连接到衬底上，特别是用于高可靠性或高温要求。除了空隙化之外，由于多种原因（例如污染），在烧结期间还可能发生粘附问题。与体积缺陷不同，单纯的粘附问题无法通过X射线检测。因此，必须应用其他方法来进行过程监控。本研究比较了不同的无损成像技术对烧结层缺陷检测的优缺点。除了X射线，扫描声学显微镜（SAM）和锁定热成像方法（DLIT + ILIT）进行了研究和评估的适用性检测不同的缺陷类型，分辨率（最小缺陷尺寸），检测时间和可能的集成到组装过程。
In typical power electronic modules several semiconductor dies such as MOSFET or IGBT are soldered to a DBC substrate. During module production the quality of the solder layers can be monitored by the use of X-ray inspection and the void rate can be determined. Recently, the more robust Ag-sinter technology is deployed for attaching the power dies to the substrate, especially for high reliability or high temperature requirements. Besides voiding also adhesion problems can occur during sintering due to multiple reasons (e.g. contamination). In contrast to volume defects, pure adhesion problems cannot be detected by means of X-rays. Accordingly, other methods have to be applied for process monitoring. The present investigation compares the advantages and disadvantages of different non-destructive imaging techniques towards the detection of defects in sinter layers. Besides X-ray, Scanning Acoustic Microscopy (SAM) and Lock-in Thermography methods (DLIT + ILIT) were studied and evaluated in terms of suitability for detecting different defect types, resolution (minimum defect sizes), inspection time and possible integration into the assembly process.