Performance of Solder Bond on Thermal Mismatch Stresses in Electronic Packaging Assembly

Abstract

Thermo-mechanical stresses have been considered one of the major concerns in electronic Packaging assembly structural failure. The interfacial stresses are often caused by the thermal mismatch stresses induced by the coefficient of thermal expansion (CTE) difference between materials, typically during the high temperature change in the bonding process. This research work examined the effect of bond layer on thermal mismatch interfacial stresses in a bi-layered assembly. The paper verified the existing thermal mismatch solder bonded bi-layered analytical model using finite element method (FEM) simulation. The parametric studies were carried out on the effect of change of bond layer properties in order to provide useful references for interfacial stress evaluation and the electronic packaging assembly design. These parameters included CTE, temperature, thickness, and stiffness (compliant and stiff bond) of the bond layer. The recent development on lead free bonding material was being reviewed and found to have enormous potential and key role to address the future electronic packaging assembly reliability.

Themo-mechanical Interfacial Stress Analysis in Electronic Packaging at Different Temperature Conditions: Revisit Author’s Work

“…(12) it can be observed that when gradient in materials is zero (∆T 1 =∆T 3 ) and (∆T 2 =∆T 4 ), the term A 2 becomes zero and eq. (10) and (11) reduces to (7) and (8), which are the differential uniform temperature model. It is also observed that the correction factor A 2 (in eq.…”

“…As a result, a generalized form of the bi-material model is required to be constructed which should be able to take care of any temperature condition in the layers. The effect of heat generation on interfacial stresses due to the presence of a heat source in a layer is also needs to be investigated [1][2][3][4][5][6][7].…”

Bond Layer Properties and Geometry Effect on Interfacial Thermo-mechanical Stresses in Bi-material Electronic Packaging Assembly

“…Unfortunately this induced thermo-mechanical mismatch stress is one of the main causes of mechanical and functional failure in electronic and photonic devices. As the power requirement of the devices increases, the problem with thermal mismatch assumes a major cause of failure in electronic packages [1][2][3][4][5][6][7][8].…”

“…Suhir showed that for relatively small assemblies, compliant attachment could indeed result in substantial stress relief in both the adherents and the adhesives. Sujan proposed a model for shearing and peeling stresses at the interface of bi-material assembly which satisfies the interface compatibility by matching of strains at the interface rather than the actual displacements as in Suhir's work [1,6,[13][14][15]. As a consequence, an unnecessary integro-differential equation was avoided by solving only a simpler second order differential equation.…”

“…2t 0 /3G 0 , t 0 /3G 0 , and t 0 /G 0 . Sujan proposed shear stress compliance with complete derivation eliminated the contradiction of using different compliance expressions by earlier researchers [4,6,15 ]. In this study a closed form model of bi-layered assembly is used with the up-to-date bond layer shear stress compliance expression [4].…”