Grow-your-own approach to wiring 3D chips

When the island of Manhattan became too crowded, architects responded by building skyscrapers. The increasing density of components on "flat" computer chips is encouraging similar ideas, building upwards to create three-dimensional chips. But moving from flat interconnecting wires to 3D ones to link up different "storeys" has proved a tricky business – until now.

Instead of soldering prefabricated wires in place, as is traditionally done to connect two parts of a chip, Min-Feng Yu and Jie Hu at the University of Illinois at Urbana-Champaign have developed a technique to grow tiny 3D wires in situ which are tailor-made for their location.

Yu and Hu's technique is a modified form of electroplating, in which an electric current is used to coat a conductive surface with a thin layer of metal, deposited from a liquid electrolyte. Such a technique theoretically offers a way to directly "write" metal wires onto a surface.