Characterization of Oxidation-Controlled Cu for 3D-Chiplet Integration

Chiplet integration has garnered significant attention as a key enabler for next-generation AI architectures. Copper is still the majority for the interconnect material in the chiplet integration. In this study, we developed novel Cu by electrodeposition, which has been successfully tuned for oxidation susceptibility to unveil their impact on the process performance. These Cu are particularly attractive for semi-additive Cu RDL, TCB UBM/Cu pad and potentially hybrid bonding as its applications. As Cu B exhibits grain growth upon low-temperature annealing, effectively suppressing oxidation. Furthermore, this study provides insights into the differences in corrosion behavior and polishing rates during CMP. Additionally, we evaluate the surface of O₂ plasma-treated Cu after pre-bonding anneal to assess the formation of oxide layers induced by plasma treatment.