A COMPLETE MODEL OF LIFETIME DISTRIBUTION FOR ELECTROMIGRATION FAILURE INCLUDING GRAIN-BOUNDARY AND LATTICE DIFFUSIONS IN SUBMICRON THIN-FILM METALLIZATION

A complete model of electromigration failure lifetime distribution is illustrated in detail in this paper. The proposed theory can be divide d into two portions: the physical model and the statistical model. As a result of the combination of these models, the electromigration life time distribution as a function of line width and temperature is gener ally predicted. Experiments have been conducted to verify the validity of this model and reported previously. Various theoretical aspects an d implications of this model are discussed in this paper. Empirically, it is found that a significant portion of the increase in the shape f actor with the decrease in line width can be attributed to the increas e in the temperature standard deviation for narrower lines. Based on t his model and coupled with the experimental observations, it is shown that the design rule scaling suffers a steep drop with line width in t he deep submicron region. As a result, it will be difficult for the ba mboo structure in practice to salvage thin film metallization from ele ctromigration susceptibility for deep submicron microchip technologies . In order to meet the reliability specification for deep submicron de vices, other alternatives are considered and discussed.