Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling
Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling
复制标题
DOI：
10.1007/s11664-023-10870-4
复制
发表时间：
2024-01
影响因子：
2.1
通讯作者：
P. Agyakwa;S. Robertson;J. Dai;B. Mouawad;Zhaoxia Zhou;Chang Liu;C. M. Johnson
中科院分区：
文献类型：
--
作者：
P. Agyakwa;S. Robertson;J. Dai;B. Mouawad;Zhaoxia Zhou;Chang Liu;C. M. Johnson
本文研究了烧结纳米银粘结剂作为宽带隙功率模块芯片连接技术的性能。本文专门探讨了功率循环下高度多孔烧结附件的精细尺度微观结构，以更深入地了解孔隙率作为可靠性相关微观结构参数的意义。评估在220°C下使用6 MPa的压力持续Is（从先前的工作已知的参数产生大约50%的孔隙率）制备的并且随后在50°C和200°C之间经受650，000次功率循环的陶瓷。一个相关的工作流程集成X射线计算机断层扫描，聚焦离子束（FIB）和电子背散射衍射（EBSD）数据合并的介观和纳米尺度的微观结构特征，照亮降解机制。的烧结银层具有高体积的不均匀分布的孔隙，并由随机取向的等轴晶粒，其大小取决于采样区域的局部密度而变化。功率循环促进晶粒生长和孪晶界的损失，这些变化在Ag附着的更致密区域内更明显。相比之下，铜基板似乎经历了一些晶粒细化，在功率循环期间，在晶粒更细的区域内可见变形孪晶。裂纹，这似乎开始内的银层，传播的银-铜边界和transgranularly通过细晶粒区域内的铜几乎没有曲折。这些观察结果在可靠性行为的背景下进行了讨论。图形摘要
This paper deals with the performance of sintered nano-silver bonds used as wide-bandgap power module die attachment technology. The paper specifically explores the fine-scale microstructures of highly porous sintered attachments under power cycling to provide a deeper understanding of the significance of porosity as a reliability-related microstructural parameter. Attachments prepared at 220°C using a pressure of 6 MPa for 1 s (parameters known to generate approximately 50% porosity from previous work) and subsequently subjected to 650,000 power cycles between 50°C and 200°C are assessed. A correlative workflow integrating x-ray computed tomography, focused ion beam (FIB) and electron backscatter diffraction (EBSD) data is applied to merge meso- and nanoscale microstructural features to illuminate the degradation mechanisms. The as-sintered Ag layer has a high volume of heterogeneously distributed pores, and consists of randomly oriented equiaxed grains whose sizes vary depending on the local density of the region sampled. Power cycling promotes grain growth and the loss of twin boundaries, and these changes are more pronounced within more dense regions of the Ag attachment. In contrast, the copper substrate appears to undergo some grain refinement, with deformation twins visible within finer-grained zones during power cycling. Cracks, which appear to start off within the Ag layer, propagate across the Ag-Cu boundary and transgranularly through fine-grained regions within the copper with little tortuosity. These observations are discussed within the context of reliability behaviour.Graphical Abstract