Modelling Framework to Capture Differences

2026 27th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), doi: https://doi.org/10.1109/EuroSimE69483.2026.11511968

Modelling Framework to Capture Differences in Anisotropy Between Primary and Secondary Creep Deformation in Solder Interconnects During Rapid Temperature Excursions

Aniket Bharamgonda¹, Pranav Srinivasan¹, Abhijit Dasgupta¹, Sharan Kishore², and Abdullah Fahim²

¹Center for Advanced Life Cycle Engineering, University of Maryland, College Park, MD, USA
²NXP Semicondutors, Austin, USA

For more information about this article and related research, please contact Prof. Abhijit Dasgupta.

Abstract:

Electronics packaging increasingly relies on heterogeneous integration with high-density solder interconnects, where the thermomechanical reliability depends strongly on the creep behavior of solder alloy under varying thermal cycling ramp rates. The small length scale results in oligocrystalline joints whose deformation depends on grain-scale anisotropic mechanics. This study develops a continuum-scale anisotropic framework to predict variability of SAC305 solder joint deformation during different loading conditions. A modified Hill–Darveaux creep model with separate Hill constants for primary and secondary creep is calibrated using virtual data from a dislocation-mechanics-based crystal viscoplasticity model. The formulation is implemented through user material (UMAT) definitions in Abaqus. Simulations compare responses with and without primary creep to quantify its influence on variability of deformation and creep work in oligocrystalline solder geometry.

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