2026 27th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), doi: https://doi.org/10.1109/EuroSimE69483.2026.11511983

Effect of Underfill Interfacial Delamination on Reliability of Advanced Electronic Packages

Pranav Srinivasan¹, Aniket Bharamgonda¹, Abhijit Dasgupta¹, Rohit Gandhi², Christopher Bailey², and Georgios Dogiamis<sup>3

1</sup>CALCE, Mechanical Engineering, Univeristy of Maryland, College Park, MD, USA
²Mechaincal Engineering, Arizona State Univeristy, Tempe, AZ, USA
³Deca Technologies, Chandler, AZ, USA

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

Abstract:

Real-time, high-throughput applications such as AI/ML and connected vehicles require advanced packaging with heterogeneous integration for high performance and thin form factors. Underfills delaminate or crack due to interfacial stresses and stress concentrations, motivating modeling approaches to capture resulting failure modes and effects. While cracks in the underfill (bulk and interfacial) will not immediately affect the operational performance of the package, it will reduce the overall reliability of the electronic package because of the changes in the load distribution. It is necessary to have a simplified modelling scheme to quantify the effect of underfill cracks on the stress distribution in the die, μbumps, and redistribution layers (RDL) of the substrate. A multiscale global-local finite element thermal cycling simulation in the range between -55 and 125 °C is conducted in this paper to assess the effect of the underfill interfacial delamination on the thermomechanical reliability of an advanced heterogeneously integrated multi-chiplet semiconductor package on an ultra-fine pitch organic substrate. A global model with simplified geometry, a coarse mesh, and linear elastic material properties is first developed for the overall package. Local models of the critical region with more detailed geometric features, finer meshes, and nonlinear viscoplastic material properties are seeded with cracks of varying sizes at the underfill interfaces. Stress, strain, and energy distributions are compared in the die, μbump, and RDL, before and after underfill-RDL delamination.

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