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Pure Bollocks Issue 22_017
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* F E A T U R E S *
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The incredible shrinking system
Imagine a robot surgeon so small that it can be injected into the
bloodstream, or a miniature computer that can store 10 million times as
much data as the most powerful mainframe.
Scientists today are already working on techniques that will make this
possible although, admittedly, not until the next millennium. Known
as nanotechnology, the technique of manufacturing to tolerances of a
billionth of a metre is now the object of active research worldwide.
The Japanese Ministry of International Trade and Industry (Miti) has
already provided 95m research, while in the UK nanotechnology is the
focus of a 6m Link programme of collaborative research between academia
and industry.
Yet true nanotechnology is still a dream. The best we can hope for
now is micromechanics, the technology of producing millimetre sized
tolerances. These devices, which include the silicon sensors that are just
beginning to enter general use in cars, use standard electronic
manufacturing techniques such as chemical etching, photolithography and thin
film deposition. Now 'smart' sensors complete with pre-processing electronics
or full signal processing are just beginning to take off.
Other micromechanical devices include actuators that can adjust the
position of read heads in cd players and vcr spindles and heads.
UK expertise in this area is concentrated on techniques for fabrication
to very high tolerances and associated instrumentation. For
example, Cranfield Precision Engineering, associated with Cranfield
Institute of Technology in Bedfordshire, has produced the Nanocentre
250, a three axis computer numerical controlled system with resolution
down to 1.25nm.
At the National Physical Laboratory in Teddington, research is
concentrating on nanometre metrology. The laboratory's engineers have
designed measuring instruments with ranges from 0.05 to 15nm for optical
systems. Techniques for measuring roundness down to 1nm and displacement
calibration to 0.01nm have also been achieved.
UK research has been co-ordinated under the Link programme, under
which two industrial partners and one higher education establishment
collaborate. There are already five nanotechnology projects underway
including micromachining by focused ion beams and ultraprecision machining
research.
As Dr David Robinson of the mechanical and optical metrology division
of the NPL and the Link nanotechnology programme co- ordinator pointed
out, the priority areas for funding are machining and nano
positioning and control for photonic and optoelectronic devices.
"But future directions could be ultra small computers a thousand
times faster and with a million times the memory, microscopic robots
and perfect crystals," he said at a recent Institute of Physics conference
on the subject. "If you can make the case there will be sufficient funding."
The Japanese are, not surprisingly, keen on nanotechnology research.
In fact Professor Norio Tangaguchi, an influential Japanese academic,
coined the term in 1974. But much of their research is not performed as
part of a systematic programme, according to Kiyoshi Lizuka who runs the
Research Development Corporation of Japan's Yoshida nanotechnology project.
The nanomechanism project, one of the few ordered research efforts in
nanotechnology, has covered mainly techniques for optical devices. For
example, a one axis stage mechanism for nanometre positioning has been
designed using a synchronous linear motor and rolling ball guide to give an
accuracy of nm and a maximum speed of 200nm/s.
"Precise position control technology has been advanced by the
semiconductor and equipment industries in companies such as NEC, Mitsubishi,
Nikon and Canon because they require the most advanced technology
themselves", said Lizuka.
The Japanese team has also used a scanning tunnelling microscope
(stm) to observe features that are less then 1nm in size. In fact they have
actually observed how structures form in semiconductor substrates.
"We have built an stm which we positioned on top of a wafer and
inspected small areas on unbroken, patterned silicon wafers of up to 150nm in
diameter," he said. "This microscope has three micromanipulator probes which
are used to provide voltage inputs to transistor structures on the wafer."
Stm techniques are also being widely used in the US. "Stms are
becoming a key factor in the development of nanotechnology in the US," said
Dr Clayton Teague of the National Institute of Standards and Technology in
Maryland.
Last year scientists at IBM's Almaden Research Centre in San Jose
pinned down single atoms using an stm. A needle tip was passed over a
surface to detect bumps of protruding atoms, then a burst of current was used
to stick single atoms to the surface and pull them off. Admittedly,
though, this experiment was performed on xenon atoms at liquid helium
temperatures.
Eventually this technique could be used with semiconductor materials
to manufacture minute devices and even complete machines, according to
Dr Teague.
In fact, the method of building up structures atom by atom was the goal of
the late US physicist, Professor Richard Feynman. In a lecture at Christmas
1959 meeting of American Physical Society at California Institute of
Technology entitled "There's plenty of room at the bottom", he made some
startling predictions.
According to Prof Feynman, we could store all 50 million volumes
every published in a 'book' the size of a speck of dust, while a car could
be miniaturised 4000 times and molecular computers could think like the
human brain.
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