Leakage, breakdown, and TDDB characteristics of porous low-k silica-based interconnect dielectrics

The reliability physics of low-k interconnect dielectrics is of great interest. Leakage, breakdown and TDDB data are presented for fluorinated silica, porous carbon-doped silica, and very porous carbon-doped silica. The breakdown and TDDB performance of the dielectrics are observed to degrade with the degree of porosity but the failure kinetics (field acceleration parameter and activation energy) seem to rather insensitive to porosity. A percolation model has been developed whereby the pores are treated as defects. The percolation model seems to describe well the observed breakdown and TDDB behavior.