Microstructural change of Ag nanoporous bonding joint and interdiffusion of Cu / Ag during thermal aging

Abstract

We proposed the low temperature solid state die-attach process using Ag nanoporous sheet for the high temperature power electronic packaging. The sound Cu/Cu joint can be achieved at 300 °C under nitrogen atmosphere through Ag nanoporous bonding method. In this study, the thermal stability of The Ag nanoporous bonding Cu/Cu joint and the interdiffusion behavior between Ag joining material and Cu substrate during thermal aging at 250 °C were investigated. The inserted Ag layer shows porous layer and this porous structure is gradually densified with extension of aging time. Kirkendall voids induced interdiffusion of Cu/Al are also identified.