Investigation of thermal transport across volume-controlled thermal interface materials

For thermal management, thermal interface materials are essential to reduce parasitic thermal resistance by filling microscopic gaps at interface. While much of previous research has focused on enhancing the thermal conductivity of the materials, the inconsistency in experimental data limits fundamental investigation in the thermal interface materials. In this work, we use a screen printing and pressing method to apply thermal interface material in a consistent manner, enabling fundamental investigation to identify an optimal bond line thickness for thermal interface material. Specifically, we apply two-dimensional array of cylindrical pillars and modulate its diameter and pitch to find an optimal volume experimentally. The thermal resistance is measured using a standard thermal interface test method, and an optimal volume of thermal interface material is experimentally determined. We apply a rheological model for the thermal interface material to estimate the optimal bond line thickness under pressure, and the model prediction agrees with experimental data within ∼89.4 %. This work establishes an experimental methodology for thermal interface material, bridging a gap between its theoretical and practical approaches. • The volume of thermal interface material is systematically controlled, and those thermal resistances are characterized. • A rheological model is applied to estimate the thickness of thermal interface material when optimally applied. • This work bridges the mismatch between the experimental data and theoretical model for thermal interface materials.