Researchers in Japan and Utah got new levels of complexity and fabrication flexibility in three-dimensional structures. From their article in Nature Nanotechnology (http://www.nature.com/nnano):

Traditionally, we improve the shape of a fabricated nanostructure by improving the fabrication method (various lithography, etching and deposition techniques) that was used to make the nanostructure1. However, this approach might no longer work when the feature size approaches the limitation of the fabrication method used. Limitations include fabrication defects (such as deviations in shape from the intended design) as well as the minimum sizes for the various dimensions of the nanostructure. When feature sizes in a device are small enough, the fabrication defects in many nanofabrication methods can become a dominant factor that determines the actual shape of the nanostructure. Although extrinsic defects can be removed by improving the process, intrinsic defects caused by the fundamental statistical nature of a fabrication process (for example, noise in photon, electron or ion generation, scattering, and variations in chemical reaction) cannot be removed. The minimum linewidth and line height are often determined by the fundamental working principle of a fabrication, and are fixed once a fabrication method is selected. Fabrication defects can degrade or even destroy the operation of a wide variety of nanodevices in electronics, photonics, magnetic systems, biotechnology and other applications. The minimum linewidth and line height can also limit device density and performance.

Rather than improving a nanostructure by improving its original fabrication method, here we demonstrate a new method, known as self-perfection by liquefaction (SPEL), which removes nanostructure fabrication defects and improves nanostructures after fabrication. This process is capable of removing both intrinsic and extrinsic defects, and also of forming new shapes that may not be achievable using conventional fabrication techniques. The method selectively melts nanostructures for a short period of time (hundreds of nanoseconds) while applying a set of boundary conditions to guide the flow of the molten materials into the desired geometry before solidification.

The abstract says:

"In order to be useful as microelectromechanical devices, carbon nanotubes with well-controlled properties and orientations should be made at high density and be placed at predefined locations. We address this challenge by hierarchically assembling carbon nanotubes into closely packed and highly aligned three-dimensional wafer films from which a wide range of complex and threedimensional nanotube structures were lithographically fabricated. These include carbon nanotube islands on substrates, suspended sheets and beams, and three-dimensional cantilevers, all of which exist as single cohesive units with useful mechanical and electrical properties. Every fabrication step is both parallel and scalable, which makes it easy to further integrate these structures into functional three-dimensional nanodevice systems. Our approach opens up new ways to make economical and scalable devices with unprecedented structural complexity and functionality."

A good development for nanotech manufacturing. And wonderful images.