Correlation between barrier integrity and TDDB performance of copper porous low-k interconnects

Time Dependent Dielectric Breakdown performance of a fully dense and a porous metal diffusion barrier was evaluated on a porous methyl-silsesquioxane low-k material. By changing the barrier deposition process, the barrier integrity on damascene sidewalls can be improved and sealing of the low-k sidewalls is achieved with a barrier thickness value of about 8 nm. A clear correlation between barrier integrity and interconnect reliability was evidenced and an improved barrier integrity leads to increased lifetimes.