Achieving clean metal surfaces, particularly oxide-free surfaces, before subsequent processes has been identified as a significant issue in interconnect technology. This study, conducted at UT Dallas, explored the impact of chemical-based vapor cleaning on Co surface using anhydrous Hydrazine (N2H4, produced by RASIRC) for interconnect applications. ex-situ XPS analysis revealed an effective surface treatment using N2H4 vapor, where features related to Co metal were clearly observed in the Co 2p XPS region compared to the as-is sample. The vapor-phase treatment contributed to the reduction of organic surface contaminant and metal-oxygen at a process temperature as low as 200 °C. Using the in-situ Reflection Absorption Infra-Red Spectroscopy (RAIRS) equipped with an ALD chamber, the reduction of surface contaminations and Co–O bonds after N2H4 exposure cycles at various process temperatures were confirmed. Overall, both ex-situ XPS and in-situ FTIR analysis validated the effectiveness of N2H4-based vapor-phase treatment on metal surface cleaning.
