Study of pore structure and stability in porous low-k interconnects using electrolyte voltammetry.

This letter presents a step-mode voltammetry method which uses ion diffusivity to characterize pore structure in both dense and porous low dielectric constant materials (low k) in patterned interconnect structures. Findings reveal that the intramolecular space in dense low k acts like a small physical pore network. It is determined that electrolyte ions can migrate through such space in dense low k, but with higher activation energy than in porous low k or the bulk solution, 0.31 eV vs 0.18–0.19 eV. Also, this study finds that the pores in ultralow k are not stable but can either coalesce or collapse depending on stress conditions. [ABSTRACT FROM AUTHOR]