Scaling Impacts and Challenges on Reliability in Cu/low-k Interconnects

摘要

In this paper, the scaling impacts on the Cu/low-k reliability are discussed from the viewpoints of electromigration (EM) and Joule heating. EM lifetime decreases in accordance with decreasing line width at a fixed current density. EM improvement effect of impurity doping has line width dependence and it causes the apparent line width dependence of lifetime. The control of impurity incorporation at the Cu surface is vital for maintaining an efficient tradeoff between resistivity and reliability. The temperature increase due to Joule heating mainly depends on the thermal conductivity of the inter-level dielectric and consumed power on the lines. The multi-level dielectric structures and the layout of lines strongly contribute to the temperature rise due to Joule heating.