Solid-Liquid Interdiffusion Bonding between Ti/Ni/Ag/Sn Backside Metallized Si Chips and Cu/Al₂O₃ - DBC Substrates with Au/Pd/Ni Surface Finish

In recent years, solid-liquid interdiffusion bonding (SLID) had received much interest from semiconductor manufacturers, primarily due to its ability as a reliable die bonding method especially under high temperatures.This paper presented the work in the optimized Si/Ti/Ni/Ag/Sn bonded on DBC Al2O3/Au/Pd/Ni/Cu substrates by SLID in a vacuum environment.The diffusion phenomenon at the bonding interfaces was observed by SEM/EDX.Well-defined layered bond structures with excellent strength exceeding 7.91 MPa were achieved for the Au-Sn SLID system.Intermetallic compounds in the form of Ag3Sn, Ni3Sn4, and Ni3Sn2 were observed at the bonding interface between Si/Ti/Ni/Ag/Sn wafers and DBC substrates.Superior bond strength of the SLID system allows applications in die bonding that fulfill the requirements of commercial semiconductor packaging specifications.