Enhancing long-term thermal reliability of sintered joints through the use of silver-coated copper particles

This study investigated the long-term thermal reliability of a sintering paste incorporating Ag-coated Cu (Cu@Ag) particles to inhibit copper oxidation . After thermal aging, shear strength increased in Cu@Ag joints under inert and air atmospheres, showing different microstructures. In an inert atmosphere , a Cu Cu sintering network emerged, while in air, atmosphere facilitated the formation of a Cu 2 O network encasing the Cu@Ag particles within the sintered joint. Subsequent analyses of the sintered joint microstructures, post long-term thermal reliability testing and differentiated by pressurization and non-pressurization in air, unveiled further disparities. Pressurized samples exhibited a dense sintering network within the joint microstructure that restricted oxygen access to copper, leading to a thin Cu 2 O shell encapsulating the copper particles. Conversely, non-pressurized samples featured a porous sintering network, enabling direct contact between copper and oxygen during thermal aging and the formation of a significant Cu 2 O bulk network. The fracture modes also varied between the pressurized and non-pressurized samples, with ductile fracture observed in the former and brittle fracture in the latter. Based on these findings, this study proposes an optimal microstructure for the Cu@Ag paste, promoting the use of a Cu@Ag sintering paste as a cost-effective and antioxidative approach for enhancing thermal reliability. • We propose an optimal microstructure for Cu@Ag paste to improve thermal reliability. • Thermal aging enhances shear strength in both inert and air atmospheres. • Inert atmosphere promotes Cu Cu network formation; air leads to Cu 2 O encasement. • Pressurization significantly influences the sintered joint's microstructure.