#CHIPS: "Researchers: Carbon better than copper for TSVs"

Three-dimensional chip stacks are better connected with through-silicon-vias (TSVs) filled with carbon nanotubes instead of copper, according to researchers at Chalmers University of Technology in Gothenburg, Sweden.



Image credit: Teng Wang, Kjell Jeppson, Lilei Ye, Johan Liu. Carbon-Nanotube Through-Silicon Via Interconnects for Three-Dimensional Integration. Small, 2011, Volume 7, pages 2,313–2,317. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.
TSVs promise to speed up the communications among all the chips that make up an electronic system by stacking them in 3-D instead of laying them out flat on circuit boards. Unfortunately, filling the vias with copper causes problems with thermal expansion, since copper expands more than the surrounding silicon. Carbon nanotubes could solve this problem.
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