Low temperature Direct Bonding of SiN and SiO interfaces for packaging applications

New challenges in packaging arise as the pitch of the first-level-interconnects shrinks below what can be achieved with solder joints. Hybrid bonding, including direct Cu-Cu bonding, is a promising solution but faces significant integration challenges.In this study, which is focused on potential use of direct bond technology for packaging applications, a model for quantifying the impact of wafer/substrate thickness to bond wave speed is presented and validated. Then, a low temperature deposited Silicon Nitride (SiN) surface is studied for both symmetrical and asymmetrical bonds. Guidance on densification needs, best surface preparation, and annealing condition to achieve sufficient bonding energy and void free bonding are reported for each interface type with low annealing temperature conditions (≤200°C). This ensures a solution can be leveraged for advance packaging applications.