A comparison of various dielectric/metal sidewall diffusion barriers for Cu/porous ultra-low-K interconnect technology in terms of leakage current and breakdown voltage

Abstract: A very thin dielectric flash layer (DFL) was used in addition to Ta for Cu/ultra-low-K (porous SiLK™) back-end technology. Atomic force microscopy showed that SiC DFL is superior to Si3N4 or SiO2 DFL in terms of smaller surface roughness. It appears to the authors that the key point to get a very smooth DFL is to avoid the use of nitrogen-containing gases like NH3, N2 or N2O during the DFL deposition process. An alternative explanation is that trimethylsilane is the better Si source compared to silane. Electrical testing showed that SiC DFL is superior to Si3N4 or SiO2 DFL in terms of higher breakdown voltage. [Copyright &y& Elsevier]