Microstructure and properties of Cu/Si composites for electronic packaging: Effect of tungsten layer on silicon particles

Cu/Si composite are ideal electronic packaging materials, but the intense formation of Cu-Si intermetallics during preparation leads to a significant decrease in their plasticity and thermal conductivity. In this paper, a W layer was formed on Si particles using the sol-gel method, and Cu/Si composites were prepared by hot pressing. The results show that the maximum thickness of the W layer is 1.64 μm, and the minimum thickness is only 809 nm. The W layer acts as a diffusion barrier, effectively inhibiting the Cu-Si interfacial reaction and intermetallics formation, thus preventing the deterioration of matrix and reinforcement properties. Compared with the Cu/Si composite, the elongation of the Cu/Si@W composite improves from 0.2% to 1.7%, and the thermal conductivity increases by 7 times to 233.9 W/(m·K). Additionally, among the four samples, the Cu/Si@W composite has the lowest coefficient of thermal expansion (CTE). The W layer enhances the mechanical properties and thermal conductivity while reducing the CTE of Cu/Si composite for improved electronic packaging application.