Aligned carbon nanotubes for through-wafer interconnects

Through-wafer interconnects by aligned carbon nanotube for three-dimensional stack integrated chip packaging applications have been reported in this letter. Two silicon wafers are bonded together by tetra-ethyl-ortho-silicate. The top wafer (100 μm thick) with patterned through-holes allows carbon nanotubes to grow vertically from the catalyst layer (Fe) on the bottom wafer. By using thermal chemical vapor deposition technique, the authors have demonstrated the capability of growing aligned carbon nanotube bundles with an average length of 140 μm and a diameter of 30 μm from the through holes. The resistivity of the bundles is measured to be 0.0097 cm by using a nanomanipulator.