Thermal analysis of advanced back-end-of-line structures and the impact of design parameters

Abstract

In this paper, we present a thermal analysis of advanced back-end of line (BEOL) structures. This analysis includes an assessment of the equivalent out-of-plane thermal conductivity of the BEOL stack, the Joule heating of metal lines inside the BEOL stack, and a benchmark study of the impact of different design parameters, material properties, via layout, and an evaluation of the specific impact of barriers. The thermal analysis is conducted with 3D finite element models of two BEOL stack examples. The comprehensive sensitivity analysis of material properties shows that the dielectric thermal conductivity strongly impacts the BEOL thermal performance, and that the metal electrical resistivity has the strongest impact on Joule heating. In addition, the metal thermal conductivity and the barriers' electrical resistivity also give significant contributions. The via density DOE shows dramatic changes in BEOL thermal conductivity. The thermal impact of the barrier is also studied for different prototypical hybrid interconnect structures.