In situ electron microscopy studies of electromigration in stacked Al(Cu)/TiN interconnects

In situ transmission electron microscopy experiments on electromigration in Al(0.5%Cu)/TiN interconnects show that the TiN barrier layer improves reli ability not only by acting as a shunting layer, but also by dramatically in fluencing electromigration behavior within the Al(Cu) interlayer. One highl ight of these experiments is a complete absence of void migration in such l ines, as opposed to Al(Cu) lines on SiO2 without barrier layer [Al(Cu)/SiO2 ]. This remarkable immobility of voids in Al(Cu)/TiN lines has a profound i mpact on failure mechanisms, lifetimes, and reliability of interconnects. T he TiN barrier layer also dramatically effects void nucleation and growth. (C) 2000 American Institute of Physics. [S0003-6951(00)04502-2].