Tape-Assisted Transfer of Carbon Nanotube Bundles for Through-Silicon-Via Applications
- 301 Downloads
Robust methods for transferring vertically aligned carbon nanotube (CNT) bundles into through-silicon vias (TSVs) are needed since CNT growth is not compatible with complementary metal–oxide–semiconductor (CMOS) technology due to the temperature needed for growing high-quality CNTs (∼700°C). Previous methods are either too complicated or not robust enough, thereby offering too low yields. Here, a facile transfer method using tape at room temperature is proposed and experimentally demonstrated. Three different kinds of tape, viz. thermal release tape, Teflon tape, and Scotch tape, were applied as the medium for CNT transfer. The CNT bundle was adhered to the tape through a flip-chip bonder, and the influence of the bonding process on the transfer results was investigated. Two-inch wafer-scale transfer of CNT bundles was realized with yields up to 97% demonstrated. After transfer, the use of several different polymers was explored for filling the gap between the transferred CNT bundle and the sidewalls of the TSV openings to improve the filling performance. The current–voltage characteristic of the CNT TSVs indicated good electrical performance, and by measuring the via resistance as a function of via thickness, contact resistances could be eliminated and an intrinsic CNT resistivity of 1.80 mΩ cm found.
KeywordsCarbon nanotube bundles postgrowth transfer TSV polymer filling resistivity
Unable to display preview. Download preview PDF.
This work is supported by EU program “Nano-RF” (Contract No. 5920631). We also acknowledge the funding from the Swedish Strategic Science Foundation (SSF) within the frame ICT project “Carbon-Based 3D High-Speed GaN Electronic Systems” (Contract No. SE13-0061). In addition, we acknowledge the support from the Chinese National Science Foundation under Contract No. 51272153, the Chinese State Scholarship Fund (CSC), as well as the Shanghai Science and Technology Commission (STCSM) Project under Contract No. 12JC1403900. This work was also carried out within the Sustainable Production Initiative and the Production Area of Advance at Chalmers University of Technology.
- 14.N. Khan and S. Hassoun, eds., Designing TSVs for 3D Integrated Circuits (New York: Springer, 2013), p. 53.Google Scholar
- 26.T. Sultana, M.N. Alam, and M.F. Hossain, (2012). doi: 10.1109/ICECE.2012.6471485.