Evaluation of Threshold Current Density of Electromigration Damage in Angled Bamboo Lines

Abstract

As silicon integrated circuits (ICs) continue to scale down, several reliability issues have emerged. Electromigration — the transportation of metallic atoms by the electron wind — has been recognized as one of the key damage mechanisms in metallic interconnects. It is known that there is the threshold current density of the electromigration damage in the via-connected line. The evaluation of the threshold current density is one of the great interests from the viewpoint of IC reliability. In this study, metal lines with two-dimensional shape, i.e. angled metal lines are treated. The evaluation method of the threshold current density is applied to the metal line. The method is based on the numerical simulation of the building-up process of the atomic density distribution in the bamboo line by using the governing parameter for electromigration damage. Comparing the evaluated results of the angled line with that of straight-shaped line, the effects of corner position and line length on threshold current density of electromigration damage are discussed.