Thermo-Mechanical Analysis of Preload Effects on Thermal Performance of Grooved Copper Pillar-Indium Foil Interfaces

Thermal interface materials (TIMs) are vital for improving the heat dissipation performance of advanced electronic packaging. This study investigates a novel grooved copper pillar-indium foil thermal interface structure to expload peload displacement on interfacial heat transfer. A coupled thermo-mechanical finite element model is developed in COMSOL Multiphysics for numerical simulatiom. We first analyze the mechanical contact responses under various preload displacements to capture the evolution of contact pressure and deformation at the copper-indium interface. On the basis of the mechanical results, an equivalent thermal contact conductance method is introduced into the heat transfer model to quantify how preload-induced interface optimization affects thermal transport performance. The temperature distribution, heat flux, thermal resistance, and thermal equilibrium characteristics of the structure are systematically investigated under varied equivalent thermal contact conductance conditions. The results reveal that increased preload displacement effectively improves the interfacial contact state between copper pillars and indium foil, thereby enhancing the overall interfacial thermal transport capability. The proposed modeling method provides an effective route to evaluate the correlation between mechanical preload and thermal performance of microscale thermal interfaces, which can guide the optimization of advanced electronic packaging structures.