Study on the bimodal filler influence on the effective thermal conductivity of thermal conductive adhesive

The thermal management for electronics systems becomes more crucial to the overall system performance as the packaging density becomes much higher and the IC power increases at the same time. Thermal conductive adhesives (TCAs) have been widely adopted in electronics systems. As an epoxy matrix with conductive fillers, it is essential to figure out the effective thermal conductivity of this composite material. In the present paper, a parameterized cubic cell model (CCM) is developed and then implemented by the finite element method to investigate the effects of the bimodal fillers on the effective thermal conductivity. In addition, a series of bimodal TCA samples are prepared and the thermal conductivities in the in-plane and vertical directions are measured experimentally. An obvious anisotropy with respect to the thermal conductivities has been observed for the bimodal filler loading under consideration. A good agreement between the numerical results and the experimental data is obtained.