A study on the thermomechanical response of various die attach metallic materials of power electronics

Abstract

PurposeIn power electronics, there are various metallic material systems used as die attachments. The complete understanding of the thermomechanical behavior of such interconnections is very important. Therefore, this paper aims to examine the thermomechanical response of four famous die attach materials, including sintered silver, sintered nano-copper particles, gold-tin solders and silver-tin transient liquid phase (TLP) bonds, using nonlinear finite element analysis.Design/methodology/approachDuring the study, the mechanical properties of all die attach systems, including elastic and viscoplasticity parameters, are obtained from literature studies and hence incorporated into the numerical analysis. Subsequently, the bond stress–strain relationships, stored inelastic strain energies and equivalent plastic strains are thoroughly examined.FindingsThe results showed that the silver-tin TLP bonds are more likely to develop higher inelastic strain energy densities, while the sintered silver and copper interconnects would possess higher plastic strains and deformations. Suggesting higher damage to such metallic die attachments. The expensive gold-based solders have developed least inelastic strain energy densities and least plastic strains as well. Thus, they are expected to have improved fatigue performance compared to other bonding configurations.Originality/valueThis paper extensively investigates and compares the mechanical and thermal response of various metallic die attachments. In fact, there are no available research studies that discuss the behavior of such important die attachments of power electronics when exposed to mechanical and thermomechanical loads.