Terminal Sinter-Bonding Using Silver Paste for Aluminum Nitride Heater

Abstract

In this study, a Ag sintered joint was applied to replace the high-Pb solder to bonding materials between Aluminum Nitride (AlN) substrates and terminals used in wafer bake processes. The Ag sintered joint was fabricated using an optimized temperature profile. The high-Pb solder specimens were fabricated using a conventional reflow process. An X-ray analysis and mechanical properties evaluation of the specimens were performed. Subsequently, a high temperature storage test was performed for a high temperature reliability evaluation. The initial void analysis result showed that the Ag sintered joint and high-Pb solder joint had approximately 1%, and 20% voids, respectively. After being stored at a high temperature of 280 ℃ for 1000 h, the shear strength of the high-Pb solder joint decreased by approximately 27% owing to the Pb degradation. However, the shear strength of the Ag sintered joint was maintained. After 1000 h of a high temperature storage test, growth of Ni3Sn4 intermetallic compound and Kirkendall voids were observed at the high-Pb solder interface. Furthermore, a Ag-Au layer was observed at the sintered Ag interface. In addition, the sintered Ag joints densificated after the high temperature storage test.