Numerical analysis of the microscopic factors influencing the thermal conductivity of Al2O3/ AIN polymer composites

The thermal interface materials (TIMs) used between a chip and a heat spreader in electronic packaging composes polymeric materials filled with particulate fillers. In this work, we focus on the numerical modeling and design of the particle-laden polymers with high packing density, in which two kinds of particles are mixed. Specifically, $\mathbf{\mathrm{A}1_{2}\mathrm{O}_{3}}$ and AIN, which are commonly used in the electronic packaging industry, are taken as the particulate fillers. Firstly, a series of microstructures of Al2O3/ AIN filled polymer composites with 75 vol% filler volume fraction are generated in GeoDict software with changing the relative content of Al2O3 and AIN. The diameters of the Al2O3 and AIN particles obey orthogonal logarithmic distribution and Gaussian distribution, respectively. Then the thermal conductivities of the structures are simulated under various microscopic factors, such as particle-particle and particle-matrix interfacial thermal resistance, etc. The results are analyzed taken advantage of the orthogonal experimental design, showing that the particle-particle interfacial thermal resistance plays dominant role in the thermal properties of the particulate composites. We demonstrate that such technique can be used to optimize the design of particulate TIMs.