Novel Advanced Low-k Dielectric for 2 nm and Beyond Cu and Post Cu Dual Damascene BEOL Interconnect Technologies

A novel class of mechanically and electrically robust advanced low-k (ALK) dielectrics has been developed. These have far lower plasma-induced damage (PID), excellent builtin Cu oxidation and diffusion barrier performance, and fundamentally more reliable TDDB. One ALK recipe has been fully evaluated as the next generation low-k interlevel dielectric (ILD) for 2 nm and beyond Cu and post Cu dual damascene BEOL¹. The dense ALK ($\mathrm{k}=3.2$) and lightly porous ALK ($\mathrm{k}=2.8-3.0$) films have high modulus ($\mathrm{E} \sim 15-33 \text{GPa}$), from $\sim 1 / 2$ to $\sim 1 / 10$ the PID of typical dense SiCOH ($\mathrm{k} \sim 2.7$ 3.2) or pSiCOH ($\mathrm{k} \sim 2.4-2.55$). The ALK Cu and $\mathrm{O}_{2}$ diffusion barrier properties enable further scaling of metal barriers, to increase Cu line volumes, reducing $\mathrm{R}, \text{RC}$ while actually improving TDDB and EM. This is confirmed for 2 nm node Cu dual damascene¹ and future subtractive Ru/airgap scheme⁹.