Low loss conductors for CMOS and through glass/silicon via (TGV/TSV) structures using eddy current cancelling superlattice structure

Superlattice structures consisting of non-ferromagnetic/ferromagnetic metals have been used to create high performance conductors for radio frequency (RF) transmission lines and low loss vias in CMOS and through silicon/glass via (TSV/TGV) structures, whose ohmic resistance and RC delays have been greatly reduced. Two permalloys of Ni₈₀Fe₂₀ and FeCo are studied as the ferromagnetic materials with low and high magnetization saturation that can be used for designing superlattice structures with low and high GHz frequency ranges, respectively. The effects of design parameters including the number of layers and thickness ratio of the superlattice structures have been studied. Full wave simulations have been used to verify them. Finally, a radial superlattice structure consisting of Cu/NiFe layers has been implemented and its resistance has been compared with the control solid-core devices made of copper; proving the effectiveness of the proposed radial superlattice structure for reducing the RF loss.