Enhanced Reliability of Ultra-Scaled Interconnects Using Interlayer-Doped Aligned Carbon Nanotube-Metal Composites

The continuous scaling of electronic devices, coupled with the recent rise of 3D stacked circuits and packaging technology, presents ongoing challenges for today's metal-based interconnects. This study introduces a metal-interlayer-carbon composite as a high-performance alternative to conventional copper-based interconnects, effectively addressing the prevalent issues of increased electrical resistivity and electromigration in scaled-down technology nodes. Initially, the study explores the use of alternative CMOS-compatible metals such as Ruthenium (Ru) and Palladium (Pd), which exhibit better reliability and less electromigration in miniaturized environments compared to copper (Cu). To prepare for increased metal resistance in extreme scaling environments, single-walled carbon nanotubes (CNTs) were integrated with metals using a wafer-scale aligned coating method. Importantly, an atomically thin, intermittent layer was used as a charge transfer doping layer to improve the conductivity and reduce the contact resistance between interfaces. Transmission Line Method (TLM) measurements revealed significant reductions in the sheet and contact resistance of metal interconnects with the introduction of CNTs and charge transfer doping. Our findings suggest that the composite structures not only mitigate grain boundary scattering but also enhance the overall performance and reliability of interconnects in highly scaled electronic devices, showing promise for extremely scaled interconnects in next-generation 3D IC technology and packaging environments.