Practical aspects of thermomechanical modeling in electronics packaging: A case study with a SiC power package

• Published in: Microelectronics and reliability Vol. 132; p. 114514
• Main Authors: Ye, Guigen, Fan, Xuejun, Zhang, Guoqi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-05-2022
• Subjects: Finite element analysis; Homogenization; Power package; Stress singularity; Thermomechanical modeling; Volume averaging; Thermomechanical modeling; Homogenization; Stress singularity; Finite element analysis; Volume averaging; Power package
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2022.114514

In this paper, we presented several practical aspects for building robust and reliable finite element models in thermomechanical modeling in electronics packaging using finite element analysis. Firstly, for layered or patterned structures, a homogenized equivalent model, with equivalent orthotropic material properties, gives excellent agreement with the exact finite element model solutions. Such a simplified finite element model provides an efficient way for structural parameter optimization. Secondly, the finite element mesh should keep the fixed size and shape at the location of interest where the singular point exists. This approach provides a simple way for relative stress comparison in different designs, although the absolute value of stress components has no actual meaning. Thirdly, to further eliminate the mesh dependency, the volume averaging method can be used. We extended the local volume averaging method for large-area die attach problems. Fourthly, in this paper, we presented a comparison study between linear elastic and nonlinear viscoplastic analysis, and demonstrated that in some cases, two different types of analysis give opposite trend results. Lastly, we demonstrated that with the use of different stress components, the conclusions may be different. We also provided an ANSYS APDL script in the supplemental material as a benchmark example.
•Homogenization approach provides efficient way for structural parameter optimization.•Plastic analysis shows completely different results based on a linear elastic analysis.•Finite element mesh should keep the fixed size at singular point.•Averaging approach are presented to eliminate the mesh dependency.