The effects of sintering parameter to the microstructure and thermal properties of CuSiC composite for electronic packaging application

Abstract

Microelectronics and nano-electronics play a prominent role in current technologies and will do so to a greater extent in the future. The availability of suitable new materials for the electronic packaging is critical to the continuing advancement (miniaturisation and integration) of electronic components. As matter of fact, a plethora of new products/processes have been brought-in over the last few years. Much of the materials and microstructure research related to packaging has involved investigation toward better thermal management. Miniaturisation of electronic chips which have increasing functionality within the same package size has inducedsignificant increases in requirements for extraction of heat from the integrated circuit (IC). Packaging materials therefore have to be capable to conduct heat efficiently and at the same time have low coefficient of thermal expansion (CTE) to minimize the thermal stress and warping. Since copper (Cu) is a better thermal conductor than aluminium (Al), therefore, copper should be the best candidate as thermal material. With the presence of silicon carbide (SiC) as reinforcement, copper silicon carbide (CuSiC) metal matrix composite (MMC) should be able to perform better as a heat spreader or a heat sink than aluminium silicon carbide (AlSiC) metal matrix composite. In the present study, the focus was toward development of light weight metal matrix composite with high ceramic contents, good thermal dissipation and easy of processability. Copper silicon carbide was chosen as the material basis for focused investigation to solve thermal management problems presented by current IC systems. Powder metallurgy routes were chosen to fabricate the MMC based on this materials system. Copper and silicon carbide powders were mixed together in a planetary ball mill, and the green articles were then compacted and sintered to produce the final product of CuSiC. The effects of sintering parameters were investigated for their effects towards the produced composite density, porosity and specific heat capacity. Sintering parameters investigated included temperature, heating duration and the gaseous environment. Upon sintering, the CuSiC particle bond to one another giving a higher strength and a possibility in attaining desirable density. The higher in density and the lower in porosity of the CuSiC composite, will create a low specific heat capacity characteristic which is closer to the specific heat capacity of pure copper (Cu). Thus to achieve the lower specific heat capacity, the amount of porosity in the CuSiC composite must be minimized through the optimization of the sintering parameters.Finally in a nutshell, in order to boost the specific heat capacity of the CuSiC, the recommended sintering parameter suggests that the CuSiC composite should be sintered at 950oC for seven hours in nitrogen gas