Thermal conductivity and fire resistance of epoxy molding compounds filled with Si3N4 and Al(OH)3

Abstract The production of composites of epoxy molding compounds (EMCs), which can feature a good balance between thermal conductivity and flame-retardant behavior in terms of flammability and burning behavior, was achieved by incorporating high thermal conductivity Si 3 N 4 and flame retardant Al(OH) 3 (ATH) fillers in the epoxy matrix. The experimental results were obtained from thermal conductivity measurements and limiting oxygen index (LOI) and UL-94 tests. These results showed that the Si 3 N 4 filler has a great influence on thermal conductivity, which markedly increased for Si 3 N 4 volume fractions >40%, whereas the ATH filler greatly improved the flame resistance of EMCs. The simultaneous presence of both Si 3 N 4 and ATH fillers in the EMCs positively influenced both properties. The aim of this study was to produce composites suitable for electronic packaging applications: an optimum combination of the two fillers was determined for a total volume fraction of fillers in EMC of 60 vol.% and a volume ratio of Si 3 N 4 :ATH at 3:2; this composite had a thermal conductivity of 2.15 W/m K, an LOI of 53.5, and a UL-94 vertical burning test ranking of V-0.