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.