Electromigration of Cu Interconnect Lines Prepared by a Plasma-based Etch Process

摘要

The electromigration performance of Cu lines patterned by a Cl_2 plasma-based etch process has been studied with the accelerated isothermal lifetime test. An electromigration activation energy of 0.6 eV and a current density acceleration exponent of 2.7 were obtained. Both the copper-silicon nitride cap layer interface and the copper grain boundary were active diffusion paths. The applied mechanical bending stress changed the electromigration void distribution in the film, which leaded to the shorter lifetime and lower activation energy.