Damascene process for air-gap Cu interconnects using sacrificial layer HSQ

We proposed and demonstrated an air-gap Cu interconnects using the damascene architecture and HSQ (hydrogen silsesquioxane) wet etching sacrificial process. The SEM cross-section images of Cu air-gap interconnect with different diffusion barriers fabricated by using the damascene architecture and HSQ sacrificial process are investigated. The line-to-line leakage current conduction mechanisms of air-gap Cu interconnects with the lining layer Ta was studies in our work. The leakage current mechanism of air-gap Cu interconnects using the novel HSQ sacrificial process is Schottky emission. The process is simple, performed at room temperature, and easy to integrate with the Cu damascene architecture for the future air-gap Cu interconnection applications