title: Vertically aligned CNT-Cu nano-composite material for stacked through-silicon-via interconnects.
abstract: For future miniaturization of electronic systems using 3D chip stacking, new fine-pitch materials for through-silicon-via (TSV) applications are likely required. In this paper, we propose a novel carbon nanotube (CNT)/copper nanocomposite material consisting of high aspect ratio, vertically aligned CNT bundles coated with copper. These bundles, consisting of hundreds of tiny CNTs, were uniformly coated by copper through electroplating, and aspect ratios as high as 300:1 were obtained. The resistivity of this nanomaterial was found to be as low as ∼10(-8) Ω m, which is of the same order of magnitude as the resistivity of copper, and its temperature coefficient was found to be only half of that of pure copper. The main advantage of the composite TSV nanomaterial is that its coefficient of thermal expansion (CTE) is similar to that of silicon, a key reliability factor. A finite element model was set up to demonstrate the reliability of this composite material and thermal cycle simulations predicted very promising results. In conclusion, this composite nanomaterial appears to be a very promising material for future 3D TSV applications offering both a low resistivity and a low CTE similar to that of silicon.
authors.affiliation: SMIT Center, School of Mechanical Engineering and Automation and Institute of NanomicroEnergy, Jiading Campus, Shanghai University, 201800 Shanghai, People's Republic of China. Electronics Materials and Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
authors.forename: Shuangxi
authors.initials: S
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Mu
authors.forename: Michael
authors.initials: M
authors.lastname: Edwards
authors.forename: Davide
authors.initials: D
authors.lastname: Mencarelli
authors.forename: Luca
authors.initials: L
authors.lastname: Pierantoni
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Fu
authors.forename: Kjell
authors.initials: K
authors.lastname: Jeppson
authors.forename: Johan
authors.initials: J
authors.lastname: Liu