DNA scaffolding might be used for chips

Building blocks of life to become building blocks of circuits.

Scientists at the California Institute of Technology and IBM have discovered a way to overcome the size limitations of current chip fabrication methods by using DNA molecules as ‘scaffolding' to reach resolutions of 6nm.

Currently, chip-makers are bumping up against the challenge of fabricating semiconductor features smaller than 22nm. But the approach suggested by Paul Rothemund of Caltech could enable sub-22nm lithography.

The method calls for DNA molecules to be arranged in the shape of the desired circuit on the semiconductor substrate. Attached to the DNA molecules would be millions of circuit components, such as carbon nanotubes, nanowires and nanoparticles.

The technique for laying down the DNA scaffolding is known as DNA origami, in which a long single strand of viral DNA is folded into a shape using shorter 'staple strands'. The short staples can be modified to provide attachment sites for the nanoscale components.

The team at Caltech that pioneered DNA origami reckons it can be scaled down to define features as small as 6nm.
However DNA origami structures are usually synthesised in a solution, which can't be deposited with any accuracy. So Caltech and IBM have come up with a way to use electron-beam lithography and dry oxidative etching, as per conventional chip fabrication, to create DNA origami-shaped binding sites on the substrate.

Key to the process were the discoveries of the right template material and deposition conditions to afford high selectivity so that the origami binds only to the patterns of "sticky patches" and nowhere else.

If you're not sufficiently boggled by this and want more details, you can read the research paper penned by Caltech and IBM.