The system, developed by Radiance Services based in Washington DC, is being
tested by the US Department of Defense. The DoD is using the lasers to remove
microscopic dirt particles from semiconductor wafers at its fabrication plants
in Maryland and California.

The laser system could eventually replace solvents such as hydrogen peroxide,
hydrochloric acid and ammonium hydroxide, all of which are currently used to
remove dirt particles as small as 0.9 micrometres during manufacture. As the
components on computer chips shrink dust becomes a bigger problem.

A deep ultraviolet excimer laser has been integrated into the manufacturing
process to zap any dirt particles that make it onto wafers in the clean rooms
where chips are made. These high-powered lasers break the bonds between dirt
particles and the component’s surface.

Radiance estimates that lasers could clean chips and circuit boards for a
seventh of the price of solvents. They would also free electronics companies of
the burden of having to produce or buy de-ionised water to wash solvents away.
Radiance says a typical electronics plant in the US creates between 3 and 6
million gallons of waste water a day that has to be treated to remove harmful
chemicals.

Trials will continue until September as Radiance researchers determine what
the lasers can and cannot remove. But Radiance is also fielding calls from other
industries requiring precision cleaning. Donna Fitzpatrick, director of
Radiance, says: “We are looking at laser cleaning for a huge variety of
products, from hard discs to brass doorknobs to titanium jet engines.”

Nico van den Brink of the Institute for Forestry and Nature Research in
Wageningen, the Netherlands, looked for volatile organic chemicals in the oil
that birds produce for preening their feathers. He focused in particular on
hexachlorobenzene (HCB), which is released into the air from industrial
incinerators and other plants. HCB can interfere with birds’ ability to
transport oxygen around their bodies.

Levels of HCB in preen oil samples from five Antarctic species—the
Adélie penguin, the southern fulmar, the snow petrel, the Antarctic
petrel and the pintado petrel—were hundreds of times higher than the
levels found in oil from common terns living on the Dutch Waddenzee. Oil from
pintado petrels contained 1808 nanograms per gram of HCB, compared with just 3
nanograms per gram for the Waddenzee terns, van den Brink reports in The
Science of the Total Environment (vol 198, p 43).

“Although these compounds have been found before in the Antarctic, to find
them in such large quantities is really quite remarkable,” says Ian Boyd, a
biologist with the British Antarctic Survey in Cambridge.

Van den Brink believes that volatile chemicals such as HCB accumulate in cold
parts of the world through a phenomenon known as the “cold condenser” effect.
Pollutants released in the warmer parts of the world remain as a vapour and rise
to the upper atmosphere, where they can be transported around the globe. Once
they reach the poles, however, they condense and fall to Earth.

Animals such as seabirds are most severely affected by this pollution because
they sit at the top of the food chain, and so concentrate chemicals taken up by
other organisms. “Despite its remoteness, Antarctica is being threatened by
human activities,” says van den Brink.