Effect of current crowding on vacancy diffusion and void formation in electromigration

In multilevel interconnects, current crowding occurs whenever the current c hanges direction, such as when passing through a via. We propose that in cu rrent crowding, the current-density gradient can exert a driving force stro ng enough to cause excess vacancies (point defects) to migrate from high to low current-density regions. This leads to void formation in the latter. T his is a key feature of electromigration-induced damage in very large scale integrated interconnects. (C) 2000 American Institute of Physics. [S0003-6 951(00)01908-2].