Conformation Of Thermal Conductive Channels In Epoxy Molding Compounds And Thermal Conductive Property

In this paper, a type of epoxy molding compounds (EMC) with thermal conductive paths was developed by hot pressing method. Thermal conductive paths were constructed by the pre-curing EMC particles and pre-extrusion rods. Thermal conductivity, dielectric constant and coefficient of thermal expansion (CTE) were investigated by steady-state Bi-substrate equipment for measurement of the thermal conductivity, high frequency Q measurement and instrument for CTE, respectively. The microstructure of the samples was observed by Electron Scanning Microscopy (SEM). Thermal conductive paths were designed and carried out by using different types, sizes and contents of pre-curing EMC particles and pre-extrusion rods that contained different ceramics filler. Experimental results show: i) To the EMC with hybrid filler, the morphologies show that the distribution of fillers in resin matrix is almost homogeneous, but a little aggregation particles still exist. The thermal conductivity and dielectric constant of samples enhance obviously with the filler volume fraction increasing. But the CTE of samples decrease with the filler volume fraction increasing. ii) To the EMC with pre-curing particles, the morphologies show that Si₃N₄ EMC and SiO₂ EMC combine well and interpenetrate each other. The higher volume fraction of Si3N4 in the filler results in a steady increase in the thermal conductivity and dielectric constant. But the higher volume fraction of Si3N4 in the filler results in a steady decrease in the CTE. iii) To the EMC with pre-extrusion rods, the morphologies show that the pre-extrusion rods with fiberglass are compact, and the pre-extrusion rods without fiberglass are loose. The higher volume fraction of pre-extrusion rods results in a remarkable increase in the thermal conductivity and dielectric constant. In case of different thermal conductive paths, the Si3N4 EMC filled with SiO₂ EMC particles is the best designed method.