Inverse Hybrid Bonding with Metal Oxide Framework as Infill for Heterogeneous Integration

Inverse hybrid bonding is proposed as a novel D2D/D2W bonding scheme for 3D heterogeneous integration. The bonding scheme utilizes direct copper bonding followed by optimized atomic layer deposition (ALD) of metal oxide framework (MOF) as an infill between the integrated dice. A testbed with passive dice assembled using direct copper flip chip bonding was formulated. For the assembled structure, a 5 mΩ average resistance per I/O along with a fourfold increase in the shear strength of the bonded dice after infill was observed, thereby demonstrating the potential promise of the bonding framework. Further, complete infill of a 1 μm vertical gap between integrated dice with an effective bonded area of 5 mm x 5 mm was documented using the MOF deposition process.