Synthesis And Properties Of Organic/Inorganic Composite Thermal Interface Materials

In the past few decades,the microprocessor has continued to develop along Moore’s Law,even surpassing the development trend of Moore’s Law.While meeting the increasing demand for integration and performance,its power density has also increased rapidly.As a result,the cooling needs of microprocessors are receiving increasing attention.In this thesis,some new types of high-performance organic/inorganic composite thermal interface material were prepared by aluminum-based thermal conductive fillers,epoxy resin and silicone rubber.The following research results were obtained:（1）An Al@Al₂O₃ hybrid particle with a core-shell structure was prepared by self-passivation at a high temperature,and the hybrid particle was compounded with an epoxy resin matrix to prepare an Al@Al₂O₃/Epoxy composite with thermally conductive and electronic insulating performance.The results show that the thermal conductivity of the composite material can reach 0.92 W m^-1 K^-1 when the filler content of Al@Al₂O₃ hybrid particles reaches 60 wt%,which is 4.2 times that of pure epoxy resin.The electron transfer is effectively restricted because the surface of the Al microspheres is covered with a dense insulating Al₂O₃ layer,thus leading to a very high electrical resistivity(4.6×10¹³Ω·cm)and puncture voltage（1.81 KV/mm）of the composites.In addition,through simulation of actual application scenarios,it can be observed that the composite material can effectively and quickly help heat-generating components conduct heat flow,and it also exhibits very good thermo-mechanical properties.In summary,considering all the advantages of this thermal interface material,it is expected to be applied to the field of thermal management.（2）Al₂O₃ and AlN ceramic particles are used for compound filler system,and then compounded with silicone rubber to prepare Al₂O₃-AlN/silicone rubber thermal pad with a highly thermally conductive.The results show that after surface modification of the powder with a silane coupling agent,organic functional groups were successfully"grafted"on the surface of these particles,which improved the compatibility of the powder with the silica gel matrix.Through accurate measurement of three different particle sizes of Al₂O₃,the percentage content ratios of them in the most densely packed mode were obtained by analysis and calculation of the particle packing theory.The thermal conductivity of the thermal pad prepared under the guidance of this gradation ratio can reach a maximum of 9.6 W m^-1 K^-11 at a filling content of 96 wt%,which is 1.6 times that of pure Al₂O₃/silicone rubber.It was proved that the most densely packed mode made the filler particles form more heat conduction paths,and thus the thermal conductivity was improved.Through the simulation of extreme hot and cold application conditions,it can be observed that the thermal conductivity of the thermal pad does not decrease significantly after 600cycles of hot and cold shocks,showing excellent environmental adaptability.In addition,the thermal pad also has good flexibility and conformability,and it can play the dual functions of heat dissipation and buffer protection at the same time.Therefore,the thermal conductive pad has a good application prospect in the field of high thermal conductive electronic packaging.