Thermo-Mechanical Stress Analysis in Electronic Packaging with Continuous and Partial Bond Layer

Abstract

Interfacial stress due to thermal mismatch in layered structure has been considered as one of the major causes of mechanical failure in electronic packaging. The mismatch due to the differences in coefficient of thermal expansion (CTE) of the materials in multi-layered structure may induce severe stress concentration to the electronic composites namely interfacial delamination and die cracking. Therefore, the studies and evaluation of interfacial stress in electronic packaging become significantly important for optimum design and failure prediction of the electronic devices. The thermal mismatch shear stress for bi-layered assembly can be analyzed by using the mathematical models based on beam theory. In this study, Finite Element Method (FEM) simulation was performed to an electronic package by using ANSYS. The shear stress growth behavior at the interface of the bonded section was studied with the considerations of continuous and partial bond layers in the interfaces. Based on the analysis, it can be observed that the partial bond layer with small center distances can be simplified as a continuous bond layer for bi-layered shearing stress model analysis.