Micromechanics-based interfacial stress analysis and fracture in electronic packaging assemblies with heterogeneous underfill

Author(s):  
Ji Eun Park ◽  
I. Jasiuk ◽  
A. Zubelewicz
Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2403 ◽  
Author(s):  
Shiuh-Chuan Her ◽  
Cheng-Feng Chan

The use of adhesively bonded joints in place of traditional joining techniques such as bolted or rivet joints is becoming greatly popular in recent years. Interfacial stress in the adhesive is critical to the strength of adhesively bonded joints. It is necessary to predict the interfacial stresses accurately to ensure the safety of joints. In this work, an analytical model is explicitly presented to evaluate the stresses in a double lap joint. The equilibrium equations in the adhesive overlap region are derived on the basis of elasticity theory. The governing equations are presented in terms of shear and peel stresses in the adhesive. Analytical solutions are derived for the shear and peel stresses, which are considered to be the main reason for the failure of the double lap joint. To verify the analytical solutions, the finite element method is conducted using the commercial package ANSYS. Results from the analytical solution agree well with finite element results and numerical investigations available in the literature. The effect of the adhesive thickness, shear modulus, adherend Young’s modulus and bonding length on the shear and peel stresses in the adhesive of the double lap joint are studied. Numerical results demonstrate that both the maximum shear and peel stress occur at both ends of the bonding region. The maximum values of the shear and peel stresses increase as the adhesive thickness decreases and as the adhesive shear modulus increases provided that the adhesive thickness is sufficiently small. The simplicity and capability to obtain analytical expressions of the shear and peel stresses for double lap adhesive bonded joints makes the proposed analytical model applicable for the stress analysis and preliminary structural design.


2006 ◽  
Vol 306-308 ◽  
pp. 1055-1060 ◽  
Author(s):  
Seung Jae Min ◽  
Hyoung Seok Lee

As the larger capacity and smaller packaging size are required in the design of a semiconductor, areas and pitches of solder joints have been miniaturized. Therefore the importance of bondability and reliability in soldering technique for the printed circuit board design has been increased since the fatigue failure has been observed at the place between the lead frame and solder joints. To evaluate thermal reliability of SMD type electronic packaging such as SOIC, PLCC and BGA, an exclusive module for modeling a lead frame structure is developed using JavaScript and the thermal stress analysis is performed using ANSYS. A modeling program with GUI can define geometric dimensions of an electronic packaging, assign material properties of a lead frame and a solder and apply boundary conditions. A seamless integration between modeling and analysis is achieved by implementing an interface program to generate an analysis model of a lead frame structure directly from the model information. Heat transfer analysis and stress analysis considering thermal loading are carried out in ANSYS and the results are exploited to estimate the fatigue life of a lead frame based on the S-N curve. The effect of different lead frame materials is examined to identify the mechanical characteristics and the different shapes of the lead frame with same SMD type are investigated to distinguish the reliability.


2012 ◽  
Vol 44 (6) ◽  
pp. 815-837 ◽  
Author(s):  
Sheng-Wang Hao ◽  
Yan Liu ◽  
Xiao-Dan Liu

2009 ◽  
Vol 23 (6) ◽  
pp. 2394-2401 ◽  
Author(s):  
Li-juan Li ◽  
Yong-chang Guo ◽  
Pei-yan Huang ◽  
Feng Liu ◽  
Jun Deng ◽  
...  

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