Properties Of SiC/epoxy Resin Composite Used For Electronic Packaging

Epoxy resin is a most used packaging material. However, low thermal conductivity and high thermal expansion coefficient make it not be able to meet the requirement for electronic equipment today. According to the thermal conductivity mode of Maxwell and thermal expansion mode of Kerner, adding a material with high thermal conductivity and low thermal expansion coefficient into epoxy resin could make a composite with high thermal conductivity and low thermal expansion coefficient. In this paper, we added single size SiC particles and mixed size SiC particles into epoxy to make an excellent packaging material, respectively. The relationship between the properties of the composites and the volume content of SiC was studied. As a result, the formulations of composites when they got the maximum thermal conductivity and the minimum thermal expansion coefficient were found.Epoxy resin（E51）、methy tetrahydrophthalic anhydride、liquid imidazole（R706） were used as matrix of packaging materials. The epoxy resin was solidified at 150 oC for 3 h, and the thermal conductivity, thermal expansion coefficient and bending strength of prepared solid epoxy resin were 0.296 W·m^-1·K^-1, 6×10-5 K^-1, 120 MPa, respectively.SiC particles with size of 3.5, 40 and 90 μm（named SiC3.5、SiC40、SiC90 below） were separately used to make single sized SiC-epoxy resin composites. The result showed that the thermal expansion coefficient of composites decreased as the increment of the volume content of SiC particles and increased with the increasing of SiC particle size. The thermal conductivity of composites increased as the increment of the volume content of SiC particles and the composites with SiC3.5, SiC40, SiC90 reached the maximum thermal conductivity when the volume content of SiC were 50%, 60% and 60%, respectively. The maximum thermal conductivity of the composites with SiC3.5, SiC40, SiC90 were 1.09, 1.11, 1.35 W·m^-1·K^-1, respectively.The sizes of bimodel SiC used the experiment were SiC90 and SiC3.5. Studies show that when the SiC volume ratio was 85:15 and the content of the SiC was 70%, the best comprehensive properties of the composites were obtained. The composites had the maximum thermal conductivity 1.91 W·m^-1·K^-1, the thermal expansion coefficient 6.87×10-6 K^-1, and the bending strength 71 MPa.The SiC particles modified by the coupling agent could improve the properties of the composites. When the SiC volume ratio was 85:15 and the content of the SiC was 70%, the maximum thermal conductivity of the composite was 2.15 W·m^-1·K^-1, the thermal expansion coefficient of composite was 6.69×10-6 K^-1, and the bending strength was 83 MPa.