Highly strong interface in Ag/Si sintered joints obtained through Ag2O–Ag composite paste

In this study, the interfacial strength and fracture behavior of Ag/Si interfaces formed by a composite paste comprising Ag2O microparticles, Ag microflakes, and terpineol is demonstrated through microscale tensile testing. This paste induces a delayed reduction of Ag2O and subsequent interconnection between the Ag grains and Si substrate. This is owing to the interface formation by the direct bonding of Ag and a layer with Ag nanoparticles intermediated bonding using the newly generated Ag nanoparticles. This characteristic interface formation helps achieve a high joint strength (>30 MPa) at a bonding temperature of 250 °C, inducing a substrate fracture at 275 °C. Microscale tensile testing reveals the high-strength Ag/Si (>200 MPa) interface formation and intrinsic fracture morphology within the Ag layer at a nanoscale; the fracture occurs in the Ag layer and not at the interface.