Tinier Chips, Then Life’s Tiniest Secrets
The world of high tech may be expanding at a fantastic rate, but the tools needed to continue that growth must be able to work in ever smaller places.
Microchip manufacturers need lithographic equipment that can create much smaller--and thus faster--chips. Biomedical researchers need devices that can work on the smallest scale, even at the level of DNA. Manufacturers working in super-clean environments need cameras that can photograph debris that is too small to be captured by even the sharpest lens.
One key tool used by scientists in all those areas is light, which can be used for everything from pushing atoms around to taking photos. But in the world of the future, where so many things will need to be so much smaller, the light that makes the world visible to us is reaching its limitations. The individual wavelengths of visible light are actually bigger than the tiny “objects” scientists now need to manipulate.
What they need is light in shorter wavelengths, small enough to maneuver in the nano-world of the future. They need X-rays.
For years, researchers have used giant synchrotrons at the country’s national laboratories to experiment with ways to harness the power of the X-ray for a wide range of commercial and research areas. X-rays are emitted in a synchrotron when charged subatomic particles whip around a giant tube that usually is at least as big as your average racetrack.
That research has paved the way for the use of X-rays for everything from chemical analysis to the study of atomic structure. An industrialist with a couple of billion bucks of surplus funds could probably find lots of uses for a synchrotron, but no one is standing in line to buy one, largely because of that price tag. X-ray tubes have filled the gap somewhat, but they are limited in their application.
Now a San Diego company working with the Defense Advanced Research Projects Agency and Lawrence Livermore National Laboratory, claims to have achieved a milestone that may indeed move the synchrotron onto the factory floor.
JMAR Technologies Inc., which builds precision instruments for the semiconductor and microelectronics industry, has come up with a device that company officials say will make the power of the synchrotron available for a wide range of applications. And unlike the monsters used to generate X-rays in the national labs, this device is small enough to fit on a tabletop.
“It would have to be a pretty big table,” admits John S. Martinez, chairman and chief executive of JMAR. It’s about 10 feet by 6 feet, but that’s tiny compared with a synchrotron.
The company began the project about a decade ago, leading to the development of a solid-state laser, called Britelight, one of the key components in what the company calls its “pico-second X-ray source.” The laser focuses short, powerful bursts on a target inside an X-ray chamber, heating the target up to a million degrees, Martinez said. That creates a plasma in which X-rays are generated.
“They literally come out in all directions,” he said.
But recent advances in X-ray optics developed by the Livermore lab and another firm, XOS (for X-ray Optical Systems) of Albany, N.Y., have made it possible to focus those X-rays into a powerful beam.
A single laser produces a 3-watt beam, but the company is scaling the project up through the use of several laser modules and hopes to reach 30 watts in a month or so and 90 watts by early next year. That will make it comparable to a synchrotron.
Martinez was in Washington recently briefing DARPA officials on the project, and he was accompanied by the firm’s new chief scientist, Edmond Turcu, one of the world’s foremost experts on laser-produced X-rays.
Turcu, who managed laser plasma research at Britain’s Rutherford National Laboratory before joining the company, sees a wide range of applications for the technology.
X-rays are highly energetic light waves, meaning they have very short wavelengths. The least energetic X-rays have the longest wavelengths, and they are called “soft X-rays.” The JMAR system produces soft X-rays, which are uniquely suited for many purposes. They can be used, for example, to produce an image of something that hard X-rays would pass right through.
That makes them especially useful for X-ray lithography, possibly opening the door to advanced microchips, Turcu said. A microchip is only as good as its smallest parts, and X-rays are seen as one of the most promising ways of producing ever smaller chips.
Turcu, however, is especially excited about the technology’s promise for research in radiobiology.
“Our system can deliver a huge radiation dose,” he said. “A rad [the standard unit of measurement for radiation] is a pretty big unit of dosage. This unit can deliver thousands of rads in a second. So the dose of radiation it can deliver to biological material is absolutely enormous.”
But the dosage remains concentrated in a very small area, which should allow biologists to apply a precise amount of radiation to a precise spot, thus carrying out very controlled experiments on such things as DNA.
The ability of DNA to repair itself “is the key process of life,” Turcu said. “If DNA would not repair itself, then life would vanish from the Earth.”
X-rays break just one strand of the double helix known as DNA, he said. “And then enzymes come and repair it to perfection by taking the other strand of the helix as the template,” Turcu said.
Economical and versatile X-ray devices should make it possible for biologists to study that process in much greater detail, he said.
However, the more immediate goal is to make the technology available for the microchip industry, according to company officials. The chips of the future will have to be much, much smaller, and soft X-rays may hold the key.
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Lee Dye can be reached via e-mail at leedye@compuserve.com.
