A Predictive Model for Thermal Conductivity of Nano-Ag Sintered Interconnect for a SiC Die

Nano-Ag sintering technology is a promising die attach method for power semiconductors in high reliability and high temperature (i.e. 300°C) applications. However, the present predictive models for thermal conductivity of multiphase materials are not suitable for the porous sintered Ag due to the model limitations of low porosity, i.e. < 10%, and simple pore geometry (sphere or ellipsoid). In this paper, an extension differential scheme (EDS) model based on the classical differential scheme (DS) approach has been developed. The thermal conductivity of the microporous Ag die attach layer on a SiC device was developed by measuring seven different sintering parameters that are fitted with the model. The finite element method (FEM) was also employed to analyze the influence of different factors. The results indicate that the EDS model has better adaptability and accuracy, which will be important for implementation of this new die attach material and technology.