IBM Scientists Use DNA Scaffolding To Build Tiny Circuit Boards

Nanotechnology advancement could lead to smaller, faster, more energy
efficient computer chips

SAN JOSE, Calif., Aug. 17 /PRNewswire-FirstCall/ -- Today, scientists at IBM
Research (NYSE: IBM) and the California Institute of Technology announced a
scientific advancement that could be a major breakthrough in enabling the
semiconductor industry to pack more power and speed into tiny computer chips,
while making them more energy efficient and less expensive to manufacture.

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IBM Researchers and collaborator Paul W.K. Rothemund, of the California
Institute of Technology, have made an advancement in combining lithographic
patterning with self assembly - a method to arrange DNA origami structures on
surfaces compatible with today's semiconductor manufacturing equipment.

Today, the semiconductor industry is faced with the challenges of developing
lithographic technology for feature sizes smaller than 22 nm and exploring new
classes of transistors that employ carbon nanotubes or silicon nanowires.
IBM's approach of using DNA molecules as scaffolding -- where millions of
carbon nanotubes could be deposited and self-assembled into precise patterns
by sticking to the DNA molecules - may provide a way to reach sub-22 nm
lithography.

The utility of this approach lies in the fact that the positioned DNA
nanostructures can serve as scaffolds, or miniature circuit boards, for the
precise assembly of components - such as carbon nanotubes, nanowires and
nanoparticles - at dimensions significantly smaller than possible with
conventional semiconductor fabrication techniques. This opens up the
possibility of creating functional devices that can be integrated into larger
structures, as well as enabling studies of arrays of nanostructures with known
coordinates.

"The cost involved in shrinking features to improve performance is a limiting
factor in keeping pace with Moore's Law and a concern across the semiconductor
industry," said Spike Narayan, manager, Science & Technology, IBM Research -
Almaden. "The combination of this directed self-assembly with today's
fabrication technology eventually could lead to substantial savings in the
most expensive and challenging part of the chip-making process."

The techniques for preparing DNA origami, developed at Caltech, cause single
DNA molecules to self assemble in solution via a reaction between a long
single strand of viral DNA and a mixture of different short synthetic
oligonucleotide strands. These short segments act as staples - effectively
folding the viral DNA into the desired 2D shape through complementary base
pair binding. The short staples can be modified to provide attachment sites
for nanoscale components at resolutions (separation between sites) as small as
6 nanometers (nm). In this way, DNA nanostructures such as squares, triangles
and stars can be prepared with dimensions of 100 - 150 nm on an edge and a
thickness of the width of the DNA double helix.

IBM uses traditional semiconductor techniques, the same used to make the chips
found in today's computers, to etch out patterns, creating the lithographic
templates for this new approach. Either electron beam or optical lithography
are used to create arrays of binding sites of the proper size and shape to
match those of individual origami structures. The template materials are
chosen to have high selectivity so that origami binds only to the patterns of
"sticky patches" and nowhere else.

The paper on this work, "Placement and orientation of DNA nanostructures on
lithographically patterned surfaces," by scientists at IBM Research and the
California Institute of Technology will be published in the September issue of
Nature Nanotechnology and is currently available at:
http://www.nature.com/nnano/journal/vaop/ncurrent/abs/nnano.2009.220.html.

For more information about IBM Research, please visit
http://www.research.ibm.com.

Note to registered journalists and bloggers: To view and download DNA
scaffolding images, in high or low resolution, please go to:
http://www.thenewsmarket.com/ibm.

Contact:
Jenny Hunter
IBM Media Relations
510-919-5320

SOURCE IBM

Jenny Hunter, IBM Media Relations, +1-510-919-5320