The Structure And Properties Of Al/SiCp Composites Preparated By Pressureless Infiltration For Electronic Packaging

With the development of microelectronics and semiconductor, the density of electronic packaging increases quickly, which result in the high demand to the material. Aluminum reinforced with silicon carbide particles composites is one of potential materials for electronic packaging with its excellent properties such as low density, high thermal conductivity, lower coefficient of thermal expansion etc. It is important to research the properties and preparation techniques of composites, in order to obtain the composites satisfy the application.The paper investigated the aluminum silicon carbide composites with bimodal particle distributions. The ratio of coarse and fine particles, the interface of composites, and the thermal and mechanical properties of composites were discussed in the paper.The volume fraction of reinforcement is only 55% with single particles, which is not satisfying the need of electronic packaging. Bimodal particle distribution was an effective method to enhance the volume fraction, and ratio of the coarse and fine particles is 10:1 in this paper. When particle size of 16μm and 160μm was selected, the particle volume fraction can change from 51% to 72% with the different particle proportion.In the observation of the preform, it is found that high pressure and large temperature rate will make the preform crack and then decrease the properties of preform. In addition, when SiC was oxidized in high temperature, the volume fraction of SiO₂ and thickness of SiO₂ layer were increase with the increase of temperature and holding time, and increase more quickly with the holding time.To the study of the thermal and mechanical properties of composites indicate that, the coefficient of thermal expansion was lower in composites reinforced with bimodal particles than that in the composites reinforced with single particle. The properties of preform, the flaw generated during the infiltration, and the new phase appear in the composites have effect on the coefficient of thermal expansion. The thermal conductivity of composites was increased with the decrease of the particle size. About the mechanical properties, it is found that, the bend strength of composites was decrease with the increase of particle size, and with the increase of fine particles, the bend strength increase first and then decreased. It is relative to the stress in the particles.The interface and fracture of composites were researched also. It is show that, the interface of composites is the chemical bonding, and the MgO is the main product of interfacial reaction. The fracture mechanism of composites is matrix crack, but the particle crack will be the main crack mechanism when the content of coarse or the flaw in the coarse increased. Interface breakage will be the main fracture mechanism if the interface bonding is weak because of the damage during the composites preparation.