Thermal Simulation And Thermal Properties Of Epoxy Packaging Materials

The ANSYS program was used to simulate the micro-structure of particle filled epoxy packaging materials, The effect of mesh size, particle number in models, filler shape, aspect ratio, particle long axis deviation, filler thermal conductivity, filler surface layer, filler contact, hybrid filling and size gradation filling were studied. Different fillers (Si₃N₄, Al₂O₃, SiO₂) was used to construct thermal conductive pathway through single filling, hybrid filling and size gradation filling, a part of the recipe designs by thermal simulation were verified, and the applicability of thermal simulation in the recipe designs of epoxy packaging materials was evaluated. The results indicated that: (1) Mesh size and particle numbers affects the precision of simulation results. The thermal properties of epoxy packaging materials increased with (i) the increase of particle shape factor, (ii) the decrease of deviation of filler long axis and (iii) the increase of thermal conductivity of filler surface layers. At a given value of filler content, the numerical results indicate a ratio of conductivity of filler to matrix for achieving the maximum thermal conductivity. The surface layer had a great impact on the thermal properties. (2) In the simulation of hybrid filling, thermal properties of the epoxy packaging materials increase with the decrease of volume fraction of low thermal conductive filler in total filler. In the simulation of size gradation filling, thermal properties of the epoxy packaging materials increase with the increase of volume fraction of small size filler in total filler. (3) In the experiments, thermal properties of the epoxy packaging materials increased with the filling content of the fillers, the best results were obtained by using 175μm Al2O3 in single filling, the highest thermal conductivity reached 1.94 W/m·K when the filling content was 52 vol%. Comparing with the idea of single filling, better enhancement in thermal transfer properties was achieved through size gradation filling; the best thermal conductivity was achieved in ternary size gradation filling, in this research the best thermal conductivity was obtained by using Al2O3 ternary size gradation filling(V_175μm/V_2μm/V_0.03μm=5:3:1), and the thermal conductivity reached 2.85 W/m·K when the filler content was 65 vol%. With the idea of hybrid filling, the thermal properties of epoxy packaging materials increased with the increase of filling content of total filler, and increased with the increase of volume fraction and thermal conductivity of high thermal conductive filler in hybrid fillers too, the best results was obtained by using Si3N4/SiO2 (sphere like) hybrid system. (4) In the studies of recipe designs through thermal simulation, the experimental results of single filling fitted well with the simulation results, the simulation results of hybrid filling precisely predicted the variation laws of thermal properties of the epoxy composites, all these results indicated that thermal simulation can be applied well in the recipe designs of epoxy packaging materials.