estimated time to failure (t_FE)

The time it takes for the combined stress of temperature and current density to result in a prescribed increase in resistance of the test structure (definition of failure) as determined from Black's Equation:

t_FE = A·J ^-ne^Ea/kT

where

A is an empirically determined constant, provided by the user;
J is the current density (A/cm²);
n is the current density factor, provided by the user;
E_a is the activation energy of the metallization, provided by the user (eV);
k is Boltzmann's constant (8.62 × 10^-5 eV/K);
T is the mean temperature of the test structure (K).

References