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We report on the design and fabrication of carbon nanotube (CNT) vias based on a hybrid metal/CNT technology. The CNTs were integrated on a 4 inch Si wafer platform using conventional semiconductor processes. Multiwalled carbon nanotubes were grown vertically aligned on a copper based metal line. Via holes were prepared using a single damascene process. By employing a substratebased selective deactivation of the catalyst, CNT growth was restricted to the vias. Following this process scheme, the impact of post-CNT growth procedures, like chemical mechanical planarization and sample annealing, were investigated and electrically evaluated using conductive atomic force microscopy and current-voltage (I-V) characterization. Probing 440 individual structures, the resistance of two series-connected 5 μm vias were determined to be (800 ± 60) after chemical mechanical planarization. By obtaining the I-V characteristics of single CNTs within an individual via, we found that the measured resistance is determined by the contact resistance of the CNT-metal interface. Two mechanisms were found to be relevant here. First partial oxidation of the metal interface during processing, and secondly, stress-induced voiding caused by the high temperatures during the CNT growth process. Changes in the integration scheme to reduce the overall CNT via resistance are proposed. Continuous down-scaling of the interconnect structures in ultralarge-scale-integrated electronic devices causes deterioration of the resistivity and reliability of copper lines. The International Technology Roadmap for Semiconductors (ITRS) proposed several emerging technologies to replace copper in future interconnect schemes.1 Among them, carbon nanotubes (CNT) are very promising due to their extraordinary electrical properties.2,3 Also the thermal properties of CNTs are highly beneficial for interconnect applications. Due to their one dimensional nature the thermal conduction is anisotropic with a longitudinal thermal conductivity, which can be as large as 6000 W/mK. [4][5][6] Furthermore, due to the strong sp 2 hybridized carbon bonds the CNTs exhibit an extraordinary mechanical strength leading to a large current carrying capacity, which can reach values three orders of magnitude higher than copper. [1][2][3] Currently research of CNT interconnects focuses on vias.7-18 Main challenges hereby are the compatibility with the Back-end-of-the-line (BEOL) technology requirement, 7 while simultaneously a high CNT quality and a large CNT density is required. 17 Various substrate materials for CNT growth are used by different groups. In recent reports the diffusion barrier TiN is used as conductive material. 11,12,15 Focussing on the application of CNTs for local interconnects, CNT based vias were prepared using Poly-Si as conductive substrate. 8Also CNT growth behavior on unstructured samples was investigated using Ta as substrate material, which is a typical liner material in BEOL. 19,20 Besides this work, the group of Awano, 10,13,18 incorporates a Cu line in conjunc...

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