Scaling of logic technologies to the 3nm node and beyond motivates the evaluation of new metals for the power rails and signal wires to mitigate the rising impact of interconnect parasitics on performance. The current solution based on copper and a barrier metal exhibits a significant rise in resistivity as conductor widths decrease, which leads to lower performance and higher IR drop. To support the exploration and eventual integration of alternative metals, Synopsys and IBM Research jointly performed QuantumATK atomic-scale [1,2] and TCAD Raphael FX simulations of new-generation metals (Ru, Co, W) as part of the IBM and Synopsys collaboration on accelerating post-FinFET process development with Design Technology Co-Optimization (DTCO) innovations.
The study describes a methodology for carrying out the QuantumATK simulations to account for the effects of grain boundary and surface scattering and suggests that the fcc phase of Ru could be a superior alternate conductor to Cu due to lower line and via resistance.