Research on Chemical Mechanical Polishing Mechanism of Novel Diffusion Barrier Ru for Cu Interconnect

This thesis addresses selected unsolved problems in the chemical mechanical polishing process (CMP) for integrated circuits using ruthenium (Ru) as a novel barrier layer material. Pursuing a systematic approach to resolve the remaining critical issues in the CMP, it first investigates the tribocorrosion properties and the material removal mechanisms of copper (Cu) and Ru in KIO4-based slurry. The thesis subsequently studies Cu/Ru galvanic corrosion from a new micro and in-situ perspective, and on this basis, seeks ways to mitigate corrosion using different slurry additives. The findings presented here constitute a significant advance in fundamental and technical investigations into the CMP, while also laying the groundwork for future research.

Nominated by Tsinghua University as an outstanding thesis in the field Includes a detailed experimental analysis of the surface characterization of Cu interconnects Presents advanced experimental methods for investigating Cu/Ru micro-galvanic corrosion Explains the experimental results in detail

Inhalt
Introduction.- Material Removal Mechanism of Cu in KIO4-based Slurry.- Material Removal Mechanism of Ru in KIO4-based Slurry.- Tribocorrosion Investigations of Cu/Ru Interconnect Structure during CMP.- Micro-galvanic Corrosion of Cu/Ru Couple in KIO4 Solution.- Galvanic Corrosion Inhibitors for Cu/Ru Couple During Chemical Mechanical Polishing of Ru.- Synergetic Effect of Potassium Molybdate and Benzotriazole on the CMP of Ru and Cu in KIO4-based Slurry.- Conclusions and Recommendations.