Robust Low-k Diffusion Barrier (k=3.5) for 45-nm Node Low-k (k=2.3)/Cu Integration

A robust low-k diffusion barrier, i.e., advanced SiC(O) (A-SiC(O), k = 3.5), was developed to attain a k_eff of less than 2.7 for reliable ultra-low-k/Cu integration for 45-nm node technology and beyond. A new precursor that requires that requires no oxidizing agent was introduced for deposition to obtain higher film density while maintaining the k-value. The A-SiC(O) film has a low leakage current because of its low defect density and a comparable barrier property with conventional SiC. Drastic improvement in the k_eff and TDDB lifetime were obtained by adopting A-SiC(O) without using underlying SiCN and oxidizing agent in the deposition, Reliable ultra-low-k/Cu integration was accomplished by combining A-SiC(O) and Aurora-ELK (k=2.3), which has a high modulus of 7.2 GPa, with a UV cure