K. Kim et al., "Ultralow-k Amorphous Boron Nitride Film for Copper Interconnect Capping Layer," in IEEE Transactions on Electron Devices, vol. 70, no. 5, pp. 2588-2593, May 2023, doi: 10.1109/TED.2023.3258403.

Abstract: We report the feasibility of ultralow- k amorphous boron nitride ( α -BN) film as a new capping layer for copper (Cu) interconnects. α -BN thin films were successfully deposited using a plasma-enhanced chemical vapor deposition (PECVD) process. The CVD-grown α -BN showed a k -value as low as 2.0 at 3 nm thickness, low leakage current density ( ∼7×10−8 A/cm2), and high breakdown field ( ∼ 8.8 MV/cm) comparable to a conventional SiN blocking layer. The α -BN has excellent thermal stability up to 1000 °C, implying that the film can be used not only for the back-end-of-line (BEOL) but also for the front-end-of-line (FEOL) processes. A 7-nm-thick α -BN film successfully blocked Cu diffusion at temperatures up to 500 °C. The α -BN film also showed excellent adhesion to Cu, with an adhesion energy of 2.90 ±0.51 J/ m2 between α -BN and Cu. The COMSOL multiphysics simulation predicted that, compared to a conventional SiN capping layer, an α -BN capping layer would reduce interconnect RC delay by up to 17%. The α -BN was proven to be a promising new candidate for a capping layer to reduce RC delay in Cu interconnect systems.

URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10079183&isnumber=10106527