The interaction between copper interconnects and low-fc hydrogen silsesquioxane (HSQ) fllm was investigated using a Cu/HSQ/Si metal insulation semiconductor capacitor and NH3 plasma post-treatment. Owing to serious diffusion of copper atoms in HSQ film, degradations of the dielectric properties are significant with the increase of thermal stress. The leakage current behavior in high field conduction is well explained by the Poole-Frenkel (P-F) mechanism. By applying NH3-plasma treatment to the HSQ film, however, the leakage current is decreased and P-F conduction can be significantly suppressed. In addition, the phenomenon of serious Cu penetration is not observed by means of electrical characteristic measurements and secondary ion mass spectroscopy (SIMS) analysis even in the absence of diffusion barrier layers. This indicates the copper diffusion in low-fc HSQ film can be effectively blocked by NH3 plasma post-treatment.
- Diffusion processes
- Insulator contamination
- Integrated circuit interconnections
- Low-permittivity dielectrics
- MIS devices