Microstructure characterization and thermal properties of hypereutectic Si-Al alloy for electronic packaging applications
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Zhuzhou Smelter Group Co., Ltd., Zhuzhou 412004, China)
2. Zhuzhou Smelter Group Co., Ltd., Zhuzhou 412004, China)
Abstract: The rapid solidified process and hot press method were performed to produce three hypereutectic 55%Si-Al, 70%Si-Al and 90%Si-Al alloys for heat dissipation materials. The results show that the atomization is an effective rapid solidified method to produce the Si-Al alloy and the size of atomized Si-Al alloy powder is less than 50 µm. The rapid solidified Si-Al alloy powder were hot pressed at 550 °C with the pressure of 700 MPa to obtain the relative densities of 99.4%, 99.2% and 94.4% for 55%Si-Al, 70%Si-Al and 90%Si-Al alloys, respectively. The typical physical properties, such as the thermal conductivity, coefficient of thermal expansion (CTE) and electrical conductivity of rapid solidified Si-Al alloys are acceptable as a heat dissipation material for many semiconductor devices. The 55%Si-Al alloy changes greatly (CTE) with the increase of temperature but obtains a good thermal conductivity. The CTE of 90%Si-Al alloy matches with the silicon very well but its thermal conductivity value is less than 100 W/(m·K). Therefore, the 70%Si-Al alloy possesses the best comprehensive properties of CTE and thermal conductivity for using as the heat sink materials.
Key words: Si-Al alloy; rapid solidification; thermal properties; electronic packaging application