This is part of IEEE Spectrum's special report: Winners & Losers VII
Using ultrashort light rays to print tiny features on integrated circuits has long been a dream of chipmakers, but suppliers of the necessary tools have been dashing that dream for a decade. The sources remain too weak to print more than a handful of wafers per hour, and critical parts still lack funding. As a result, Sematech, the chip-industry consortium, recently suggested that the expected rollout of the technology in 2013 might be jeopardized yet again.
”EUV’s been this bride waiting at the altar,” says G. Dan Hutcheson, CEO and chairman of VLSI Research, a firm in Santa Clara, Calif., that tracks the chip industry.
Here comes the latest bridegroom. Start-up nanoUV says it has created the world’s brightest EUV light source. The trouble is, the company won’t reveal to more than a handful of players how its technology works, making it hard to rack and stack against other options.
Hutcheson says that such a secretive strategy ”doesn’t work in this industry.” Switching to a radically new chipmaking process can cost billions, he explains, and before companies write a check for the key ingredient, they want to be sure it performs. ”There have been dozens of companies that don’t disclose. They fail because of that,” he says.
EUV, or extreme ultraviolet light, is a euphemism for soft X-rays, things that everybody in Silicon Valley knows are devilishly hard to make and focus. Whatever you call it, the radiation is attractive because its waves are around 13.5 nanometers—about as small as the features in the next generation of chips—so using them avoids the current need to print features far smaller than the wavelengths of light used to do it.
One big problem with such short rays, though, is that they get absorbed by pretty much everything, including air and glass. So you need special multilayer mirrors to focus them. A far bigger problem is that, after more than a decade of effort, nobody can yet make a decent light source. Cymer, Gigaphoton, and Xtreme Technologies, the leaders in this field, generate their EUV photons in hot plasmas that spit out fast-moving particles, making it hard to protect their light-collecting optics from the heat and debris.
We’ll do you one better, proclaims little nanoUV. The company—headed by a Brit, based near Paris, boasting a Russian chief scientist, and backed by 8.7 million (US $13 million) of venture capital from the United Arab Emirates—says its technology replaces the vulnerable light collector with a lens that’s indestructible because it, too, consists of plasma.
According to Peter Choi, nanoUV’s president and director of technology, the source has two plasmas—a very hot, tiny one surrounded by a cylindrical one. The farther you move from the center, the cooler the outer plasma becomes, dropping to a positively brisk 10 000 kelvin at the rim. As the density increases, the index of refraction decreases, which means the EUV rays bend more at the edges than in the middle, thus converging on a point. The device requires more input power than the leading light source candidates, Choi says, but because it’s just a few centimeters long, hundreds of sources can be ”multiplexed” in a many-headed ”Hydra” pattern for greater output power and brightness.