Ag Sintered Joints on ENIG Cu Substrates by an Ag-Based Complex

The sintering of Ag is a popular technique used for the die bonding of Wide band-gap semiconductor power devices. However, the presence of organic additives in Ag pastes led to the formation of an organic layer on the surfaces of Ag fillers, which hindered the sintering process. Herein, Ag nanostructures without organic additives were utilized to prepare sintered Ag joints. The Ag nanostructures were first created by thermally decomposing an Ag-based complex on electroless nickel/immersion gold Cu substrates at 180°C for 30 min. The Ag nanostructures exhibited excellent sintering performance, resulting in sintered Ag joints with a high shear strength of 35.8 MPa after being bonded at 200 °C with 5 MPa for 10 min. The microstructures of fracture surfaces and cross-sections were examined by SEM to understand the formation mechanism of dense sintered Ag joints. This study provides a promising method for preparing sintered Ag joints at low temperatures.