Preliminary design of a novel AlN-Al composite coating used for micro-electronic packaging via finite element modeling

Abstract

In this study, a novel AlN-Al composite coating (AACC) is proposed for micro-electronic packaging. By adjusting the proportion of AlN in the AACC, the effective thermal conductivity and coefficient of thermal expansion of the AACC can be controlled. The powder of AlN and Al sprayed onto the surface of the W-Cu alloy to form the AACC that acts as a buffer layer to reduce the thermal mismatch between the W-Cu alloy and microchip. Finite element simulation results show that the thermal conductivity decreases from 240.64 to 179.99 W m−1 K−1 with increasing AlN content. The coefficient of thermal expansion ranges from 8.39 to 205 MPa in the case of a selected W-Cu alloy (W70-Cu30). Some microscopic features that affect the thermal conductivity of the coating, such as porosity, pore shape, and pore orientation, have been investigated. Macroscopic properties from an SEM image of real microstructures were studied using the Object-oriented finite element (OOF) analysis.