Low-Resistivity Long-Length Horizontal Carbon Nanotube Bundles for Interconnect Applications—Part I: Process Development

Although horizontally-aligned carbon nanotube (HACNT) interconnects are the most common scenarios that have been modeled and analyzed in theoretical research, fabrication of HACNT test structures has remained an enigma until now. Through addressing several fabrication challenges, this paper reports a novel process that enables fabrication of high-density, long (over hundred microns), and thick (up to micrometer) HACNT interconnects. Furthermore, horizontal CNT-based 2-D Manhattan structure is demonstrated by properly designing the catalyst and flattening process. These structures are crucial for building angled interconnects and on-chip passive devices. In addition, to address the contact issue between metal and thick HACNT bundles, a multistep lithography combined with specifically designed metal deposition technique is performed to ensure full contact configuration. Using such a process, test structures with arrays of various sizes of HACNT bundle interconnects are fabricated. The process developed in this paper provides an important platform for future research and technology development of CNT-based interconnects and passive elements.