Studies have shown that carbon nanotubes (CNTs) may be able to replace copper in both vertical and horizontal microelectronic interconnects. This can be established by taking advantage of smaller interconnect dimensions, while keeping delay and crosstalk noise constant, thus increasing the bandwidth density of global interconnects. To date, operation of a single large diameter multi-wall CNT as a horizontal interconnect has been experimentally realized. However, challenges exist for the application of CNTs in interconnect. As key performance parameters depend on CNT length and diameter, a fabrication strategy which facilitates tunability of CNT diameter is desirable.
Researchers at the University of Michigan have developed methods to manufacture arrays of densely packed, horizontally-aligned CNTs. In this approach, arrays of vertically-aligned CNTs are first created on a substrate. This is loaded onto an apparatus, where a roller topples the CNT arrays, then contact stresses between the roller and the substrate is used to make the CNT arrays dense. The applied force can determine the thickness of the densified arrays.
Applications and Advantages
- microelectronic interconnects
- compared to copper interconnects, CNTs have smaller dimensions, resistant to electromigration and can handle higher current densities