Joule heating investigation for advanced interconnect schemes with airgaps

Abstract

In this paper, we present a modeling study to investigate the self-heating effect on advanced metallization schemes with airgaps using an experimentally calibrated finite element model. We compared N3 technology node with N2 integrated with airgaps. Despite the higher metal density of the fully dense Ru lines (50%) at the lower metal levels in the N2 structure with airgaps, the N2 stack is more susceptible to self-heating than the N3 structure with 25% line density, showing that the IMD has an important impact on the interconnect self-heating. We quantified the effect of the line density and IMD on the interconnect temperature increase. We found that decreasing the line density from 50% to 15% increases the temperature with 40% in the interconnect structure. A reduction of the low-k thermal conductivity values below 1 W/m-K shows to accelerate the temperature increase in the BEOL.