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Abstract: The reliability of microelectronic components under cyclic thermomechanical loading is an important problem especially for new leadfree solder alloys. To investigate the low cycle fatigue strength of solder joints, material models are required, that can describe the constitutive inelastic deformation and damage behavior of solder materials. Such models form the basis for advanced numerical analyses by the finite element method. In the present contribution an appropriate material model that combines the viscoplastic constitutive model of Chaboche-type with the damage law of A.C.F. Cocks for porous creep will be introduced. The algorithm is reported for an implementation as a user defined material subroutine into the FEM-code ABAQUS®. The necessary parameters of the material model are identified using results of miniaturized double lap-shear experiments and tensile tests for a Sn96Ag3Cu1 solder alloy at various temperatures. The comparison of experimental and numerical results shows a good agreement with respect to strain rate sensitivity, relaxation and damage behavior of the investigated solder material. Finally, some numerical applications to surface mounted microelectronic devices are presented. [ABSTRACT FROM AUTHOR]

Abstract: To assess the lifetime of leadfree solder joints, it is necessary to investigate their creep and failure behavior under cyclic thermo-mechanical loading. In connection with finite element analyses the use of an appropriate material model is necessary. The following paper reports on the implementation of a specific version of the viscoplastic constitutive model of Chaboche in the FEM-code ABAQUS, the experimental program for the identification of the material parameters of a Sn–Ag–Cu solder and a comparison of some numerical and experimental results. [Copyright &y& Elsevier]