Robust 45-nm Node Cu/LJLK Interconnects using Effective Porogen Control

An integration method using effective porogen control to improve the reliability of 45-nm (hp65) Cu interconnects with ultra low-k (ULK) stacked $porous-polyarylene (PAr)/porous-SiOC (k = 2.3/2.3) - hybrid dual damascene (DD) structures. By optimizing an electron beam (EB) assisted thermal cure, the target amount of porogen left in via inter layer dielectric (ILD) to enhance the etching damage resistance of the film. Quantitative analyses of the porogen amount showed that the remaining porogen was eliminated using a second thermal cure after the DD patterning. We found that the remaining porogen keeps the backbone structure of via-ILD from being damaged by active radicals during trench etching