Abstract
Solid-Liquid Inter-Diffusion (SLID) bonding is traditionally a technology used for high performance and high reliable die attach/interconnect applications. The generic properties of SLID allows the bonding to occur at a relatively low process temperature. However, when the bond is completed, the final joint has a melting point well above the process temperature. This makes it well suited as for high performance electronic assemblies. The typical bonding temperature of Cu-Sn SLID and Au-Sn SLID are 250-300 °C and 320-350 °C respectively. These temperatures compare to that of other high temperature (HT) electronic adhesives e.g. StaystikS 101G. The thermal performance of the SLID bond is superior to other electronic interface materials. This is due to the thin joint (- 10 um) and the high thermal conductivity (- 60 W/m-K for Au-Sn). Thus, the thermal resistance of a SLID joint, about 2' 10° cm~-KW. is significantly lower than most other thermo-mechanical joints suitable for use in electronic assemblies. SLID joints have also proven to be mechanically robust for harsh environment applications. In this study the thermo-mechanical properties of large Cu-Sn SLID bond are investigated. Simulations are performed to explore the stationary thermo-mechanical performance of the joint. Finite element analysis (FEA) is used to perform the simulations. The study is based on a case study involving a HT (> 200 °C) power controller device for a brushless DC motor for downhole applications. The effective strain was found to be high in the bond adjacent Cu layers but reasonably small. < 1%. within the joint itself.
