Impact of Linewidth on Backend Dielectric TDDB and Incorporation of the Linewidth Effect in Full Chip Lifetime Analysis

Low-k time-dependent dielectric breakdown (TDDB) has been found to vary as a function of metal linewidth, when the distance between the lines is constant. Modeling requires determining the relationship between TDDB and layout geometries. Therefore, comb test structures that vary pattern density and linewidth independently have been designed and implemented in 45 nm technology. Models are computed to estimate TDDB as a function of linewidth, and the cause of variation in TDDB behavior is investigated. The methodology to use the models for full-chip analysis is explained.