Study on sintering parameters and bonding mechanism of Cu@Ag preform via electromagnetic compaction for power electronics

This study investigates the low-temperature sintering and stress-assisted bonding mechanisms of Cu@Ag composite preforms fabricated via electromagnetic compaction (EMC) technology. Experimental results show that the sintering temperature, pressure, time, and internal stress significantly enhance their bonding quality, achieving a high shear strength of up to 52.01 MPa. Molecular dynamics (MD) simulations reveal that internal stress promotes plastic deformation of Cu@Ag core-shell particles, accelerates atomic diffusion, and facilitates recrystallization, reducing the required bonding energy during sintering. Consequently, this combined effect enables directly effective bonding at low temperatures without the need for intermetallic compound formation or organic solvents. These findings highlight the potential of Cu@Ag preforms as reliable die-attach materials for next-generation power electronics.