Featured Research

from universities, journals, and other organizations

Lighter Gas Reduces Damage To Optics In Extreme Ultraviolet Lithography

Date:
September 19, 2007
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers have discovered a way to generate light and reduce damage in a leading candidate for next-generation microelectronics lithography. The technique could help pack more power into smaller computer chips. In the quest for creating computer chips with ever-smaller feature sizes, chip manufacturers are exploring extreme ultraviolet lithography as the next chip-printing technology.

David Ruzic, a professor of nuclear, plasma and radiological engineering, and colleagues have discovered a technique that may help pack more power into smaller computer chips.
Credit: Photo by L. Brian Stauffer

Researchers at the University of Illinois have discovered a way to generate light and reduce damage in a leading candidate for next-generation microelectronics lithography. The technique could help pack more power into smaller computer chips.

In the quest for creating computer chips with ever-smaller feature sizes, chip manufacturers are exploring extreme ultraviolet lithography as the next chip-printing technology. For a light source at the necessary wavelength, scientists have turned to a hot, ionized gas called a plasma, generated within a Z-pinch device. But, energetic ions produced in the plasma can damage the mirror responsible for collecting the light.

"By adding a lighter gas to the plasma, we can significantly reduce the damage and extend the lifetime of the collector optics," said David Ruzic, a professor of nuclear, plasma and radiological engineering and lead author of a paper that describes the technique in the June issue of the journal IEEE Transactions on Plasma Science.

In a Z-pinch device, xenon is fed into a chamber where it collides with a stream of electrons, producing a low-temperature and low-density plasma. This plasma then flows between two cylindrical electrodes, one positioned inside the other. (The "Z" in Z-pinch refers to the direction of current flow along the cylindrical electrodes.)

Next, a large current pulse heats the plasma, while a magnetic field generated by the pulse compresses and confines the plasma. The plasma becomes hotter and denser until it "pinches," creating the flash of light needed by the chip industry.

As the pulse passes, internal plasma pressure overcomes magnetic confinement, and the hot, dense plasma flies apart. The resulting fast and energetic ions can damage the delicate collector optics.

However, adding a small amount of a lighter gas, such as hydrogen, "significantly reduces both the number and the energy of xenon ions reaching the collector surface, thereby extending the collector's lifetime while having a negligible effect on the extreme ultraviolet light production," Ruzic said. The reduction in xenon energy occurs because the hydrogen ions shield the xenon ions from the high electric field created by the plasma.

"When the plasma flies apart, the less-massive electrons move faster than the hydrogen and xenon ions," Ruzic said. "The electric field induced by the moving electrons then pulls on the ions and accelerates them. Being much lighter than xenon ions, the hydrogen ions accelerate faster, and shield the xenon ions from some of the electric field."

By absorbing some of the plasma's energy, the hydrogen ions prevent the xenon ions from accelerating to the point where they damage the collector surface, thus prolonging the collector's lifetime.

Xenon is actually the second-best radiator for light at the desired wavelength, Ruzic said. "We can get three times as much light from tin, but tin is a condensable metal and makes quite a mess on the mirrors. We are now looking at ways to clean the mirrors during chip production."

With Ruzic, co-authors of the paper are U. of I. graduate students Keith Thompson and Josh Spencer, postdoctoral research associate Shailendra Srivastava, and former postdoctoral researcher associates Brian Jurczyk and Erik Antonsen.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University of Illinois at Urbana-Champaign. "Lighter Gas Reduces Damage To Optics In Extreme Ultraviolet Lithography." ScienceDaily. ScienceDaily, 19 September 2007. <www.sciencedaily.com/releases/2007/09/070912113900.htm>.
University of Illinois at Urbana-Champaign. (2007, September 19). Lighter Gas Reduces Damage To Optics In Extreme Ultraviolet Lithography. ScienceDaily. Retrieved October 2, 2014 from www.sciencedaily.com/releases/2007/09/070912113900.htm
University of Illinois at Urbana-Champaign. "Lighter Gas Reduces Damage To Optics In Extreme Ultraviolet Lithography." ScienceDaily. www.sciencedaily.com/releases/2007/09/070912113900.htm (accessed October 2, 2014).

Share This



More Matter & Energy News

Thursday, October 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins