Kpobie W., Atintoh A., Bonfoh N., Fendler M., Koutsawa Y., Addiego F., Lipinski P.
Journal of Materials Research and Technology, vol. 40, pp. 2559-2568, 2026
The study aims to fully estimate the thermal properties of a glass fiber-reinforced woven composite laminate (FR4), using both experimental methods and numerical modeling. Differential scanning calorimetry (DSC), push-rod dilatometry and laser flash method are used to determine respectively the specific heat capacity, the coefficient of thermal expansion (CTE) and the thermal diffusivity of a FR4. A numerical homogenization approach is also implemented to predict the in-plan thermal properties that could not be experimentally measured. This numerical homogenization combined the Mechanics of Structure Genome (MSG) approach and an optimization algorithm. The properties obtained are consistent with those existing in the literature. Specific heat of FR4 increase (from 760 to 1180 J kg<sup>−1</sup> K<sup>−1</sup>) with the temperature (between 300 and 430 K). Coefficients of thermal expansion are equal to 31.9 × 10<sup>−6</sup> K<sup>−1</sup> in X direction, 31.7 × 10<sup>−6</sup> K<sup>−1</sup> in Y direction and 35.8 × 10<sup>−6</sup> K<sup>−1</sup> in Z direction (through thickness). Thermal conductivity is determined from the thermal diffusivity, specific heat and density. Their values are between 3.4 and 4.5 W m<sup>−1</sup> K<sup>−1</sup> in-plane direction and between 0.35 and 0.38 W m<sup>−1</sup> K<sup>−1</sup> in out-of-plane direction (through thickness). This high-fidelity dataset provides critical input for improving the precision of thermomechanical reliability simulations in high-density electronic packaging.
