| Popis: |
The effect of line length on the electromigration behavior of a two-level structure with Ti-AlCu-Ti stripes and interlevel tungsten (W) stud-vias has been investigated. This investigation also represents a complete study of the short-length effect using a technologically-realistic test structure. Lifetime measurements and resistance changes as a function of time were used to characterize this phenomenon, where the latter approach provides new insights into the electromigration behavior of multi-layered metallizations. A linear increase in resistance was followed by a resistance change with time that approached zero. For the same product of current density and stripe length, longer stripes increased in resistance to higher values than shorter stripes. The sigma of the lognormal distribution increased as the current density decreased and/or as the maximum allowed resistance change increased. The lifetime, or t50, at relatively small current densities did not obey Black’s empirical equation. Rather, the life... |
