Field Dependence of Porous Low-$k$ Dielectric Breakdown as Revealed by the Effects of Line Edge Roughness on Failure Distributions

We investigate the electric field (E) dependence of the breakdown of porous low-
k
dielectrics by measuring the changes in the failure time distribution resulting from the presence of line edge roughness. We show that the Weibull β increases with decreasing field, clearly demonstrating that dielectric breakdown does not exhibit 1/E or E
^-n
characteristics.