Thermal and Electrical Properties of PVD Ru(P) Film as Cu Diffusion Barrier

Thermal and electrical properties of physical vapor deposition (PVD) Ru(P) film deposited on porous ultra low-k (p-ULK) material as Cu diffusion barrier were studied. The phosphorous concentration can be tuned by adjusting Ar to PH3 ratio of the sputtering gases. The leakage current depends on phosphorous concentration. Higher phosphorous content in Ru film has lower leakage current. No obvious phosphorous content dependence was observed when the amorphous Ru(P) film crystallized. The X-ray diffraction (XRD) graphs and energy dispersive spectrometer’s (EDS) atomic depth profiles show that the Ru(P) film deposited on p-ULK can effectively block Cu diffusion when the sample is subjected to 800 °C 5 min annealing. The phosphorous doped Ru film improves diffusion barrier properties and leakage current performance. The improved Ru(P) barrier capable of direct Cu plating could be a potential candidate for advanced metallization.