Characterization of Non-Conductive Paste Materials (NCP) for Thermocompression Bonding in a Direct Bonded Heterogeneously Integrated (DBHi) Si- Bridge Package

Direct Bonded Heterogeneous Integrated (DBHi) silicon-bridge packages use known standard bond and assembly processes but require special considerations with regards to the selection of bonding materials for the bridge chip. The DBHi chip-bridge subassemblies are prepared using thermocompression bonding (TCB) with non conductive paste (NCP). In this study, we identified that the NCP encapsulated micro joints in the DBHi silicon-bridge structure are under a unique stress condition through assembling experiments and thermomechanical analysis. We evaluated and compared the properties of different NCP materials using the test vehicles specially designed to emulate the unique stress condition. We demonstrated a reliable micro solder joint structure by selecting a NCP material showing optimal chemical reaction processes and by methodically designing the bonding conditions to mitigate the fracture failures of the solder joints in the DBHi silicon-bridge.