Keep on shrinking interconnect size: Is it still the best solution?

According to the evolution between each new technological generation of CMOS ICs, ITRS suggests a reduction in interconnect sizes by a factor of around square root of 2. In this paper a reference design rule is based on a perfectly controlled technology of the CMOS 45 nm node, with interconnects width equal to their separation space. Our works are focused on the impact on signal transmission speed and delay along interconnects of decreasing the space or width. To avoid new industrial manufacturing constraints on cost and reliability, this study is performed without modifying process and materials used in the BEOL of CMOS 45 nm IC. We will study interconnects of 50 nm width, with a 50 nm space between lines in accordance with CMOS 32 nm FEOL requirements. In the second time we will relax geometrical constraints to enlarge the scope of application.