UNIVERSITY of Washington scientists working on fusion energy have found high-energy light with short wavelengths suited for etching the ultra-small features on the next generation of microchips.
As microchips become more powerful, the features on the silicon become denser, meaning smaller structures need to be etched. To do this, light with shorter wavelengths is needed, combined with sufficient power for actual etching.
Currently, the industry uses 193nm ultraviolet light, but this limits the size of the circuits that it can etch. To continue reducing the feature sizes, the industry needs light which has 13.5nm wavelength.
This extreme ultraviolet light is created from plasmas, the fourth state of matter where electrically charged gases are heated to such a high temperature that a portion of its particles are ionised.
While there have been many methods developed to create such a light, many of them are highly expensive, can only sustain the light for a short period of time, and do not provide enough power.
Fusion energy also has plasma at its core, but the scientists at the University of Washington are working on a low-cost fusion reactor which uses currents flowing through the material rather than magnets to contain the plasma. This produces stable and (relatively) long-lasting plasma.
Conventional techniques used in the chip industry generate a spark of light which lasts 20 to 50 nanoseconds. The researchers’ method produces a light beam which lasts 20 to 50 millionths of a second. While this may not seem to be a long time, it is 1000 times longer than what the industry is currently capable of.
This directly translates into more output, and more power for etching.
The plasma, the strong generated light and the controllability of the technology, prompted the researchers to spin-out a start-up company called Zplasma, which will look to commercialise the technology.