Featured Research

from universities, journals, and other organizations

New method monitors semiconductor etching as it happens -- with light

Date:
September 28, 2012
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers have a new low-cost method to carve delicate features onto semiconductor wafers using light -- and watch as it happens. The technique can monitor a semiconductor's surface as it is etched, in real time, with nanometer resolution. This allows the researchers to create complex patterns quickly and easily, and adjust them as needed.

A three-dimensional image of an etched gallium-arsenide semiconductor, taken during etching with a new microscopy technique that monitors the etching process on the nanometer scale. The height difference between the orange and purple regions is approximately 250 nanometers.
Credit: Photo by Chris Edwards, Amir Arbabi, Gabriel Popescu, and Lynford Goddard

University of Illinois researchers have a new low-cost method to carve delicate features onto semiconductor wafers using light -- and watch as it happens.

Related Articles


"You can use light to image the topography and you can use light to sculpture the topography," said electrical and computer engineering professor Gabriel Popescu. "It could change the future of semiconductor etching."

Chip makers and semiconductor researchers need to very precisely control the dimensions of their devices. The dimensions of the components affect performance, speed, error rate and time to failure.

Semiconductors are commonly shaped by etching with chemicals. Etching errors, such as residual layers, can affect the ability to further process and etch as well as hamper device performance. Thus, researchers use time-consuming and costly processes to ensure precise etching -- for some applications, to within a scant few nanometers.

The Illinois researchers' new technique can monitor a semiconductor's surface as it is etched, in real time, with nanometer resolution. It uses a special type of microscope that uses two beams of light to very precisely measure topography.

"The idea is that the height of the structure can be determined as the light reflects off the different surfaces," said electrical and computer engineering professor Lynford Goddard, who co-led the group with Popescu. "Looking at the change in height, you figure out the etch rate. What this allows us to do is monitor it while it's etching. It allows us to figure out the etch rate both across time and across space, because we can determine the rate at every location within the semiconductor wafer that's in our field of view."

The new method is faster, lower in cost, and less noisy than the widely used methods of atomic force microscopy or scanning tunneling microscopy, which cannot monitor etching in progress but only compare before and after measurements. In addition, the new method is purely optical, so there's no contact with the semiconductor surface and the researchers can monitor the whole wafer at once instead of point-by-point.

"I would say the main advantage of our optical technique is that it requires no contact," Popescu said. "We're just sending light, reflected off the sample, as opposed to an AFM where you need to come with a probe close to the sample."

In addition to monitoring the etching process, the light catalyzes the etching process itself, called photochemical etching. Traditional chemical etching creates features in steps or plateaus. For curved surfaces or other shapes, semiconductor researchers use photochemical etching. Usually, light shines though very expensive glass plates called masks that have distinct patterns of gray to let light through by degrees. A researcher must purchase or make a mask for each tweak of a pattern until the correct pattern of features is achieved.

By contrast, the new method uses a projector to shine a grayscale image onto the sample being etched. This allows the researchers to create complex patterns quickly and easily, and adjust them as needed.

"To create each mask is very expensive. That's impractical for research," Goddard said. "Because our technique is controlled by the computer, it can be dynamic. So you can start off etching one particular shape, midway through realize that you want to make some change, and then change the projector pattern to get the desired outcome."

The researchers envision this technology applied beyond etching, to real-time monitoring of other processes in materials science and life science -- for example, watching carbon nanotubes self-assemble, or error monitoring during large-scale computer chip manufacturing. It could help chip manufacturers reduce costs and processing time by ensuring that equipment stays calibrated.

The National Science Foundation supported this work, published Sept. 28 in the journal Light: Science and Applications. Goddard and Popescu are also affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I.

Graduate students Chris Edwards and Amir Arbabi were also co-authors of the paper.


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.


Journal Reference:

  1. Chris Edwards, Amir Arbabi, Gabriel Popescu, Lynford L Goddard. Optically monitoring and controlling nanoscale topography during semiconductor etching. Light: Science & Applications, 2012; 1 (9): e30 DOI: 10.1038/lsa.2012.30

Cite This Page:

University of Illinois at Urbana-Champaign. "New method monitors semiconductor etching as it happens -- with light." ScienceDaily. ScienceDaily, 28 September 2012. <www.sciencedaily.com/releases/2012/09/120928141058.htm>.
University of Illinois at Urbana-Champaign. (2012, September 28). New method monitors semiconductor etching as it happens -- with light. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2012/09/120928141058.htm
University of Illinois at Urbana-Champaign. "New method monitors semiconductor etching as it happens -- with light." ScienceDaily. www.sciencedaily.com/releases/2012/09/120928141058.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Sony Hopes To Make Any Glasses 'Smart'

How Sony Hopes To Make Any Glasses 'Smart'

Newsy (Dec. 17, 2014) Sony's glasses module attaches to the temples of various eye- and sunglasses to add a display and wireless connectivity. Video provided by Newsy
Powered by NewsLook.com
Los Angeles Police To Receive 7,000 Body Cameras

Los Angeles Police To Receive 7,000 Body Cameras

Newsy (Dec. 17, 2014) Los Angeles Mayor Eric Garcetti announced the cameras will be distributed starting Jan. 1. Video provided by Newsy
Powered by NewsLook.com
Jaguar Unveils 360 Virtual Windshield Making Car Pillars Appear Transparent

Jaguar Unveils 360 Virtual Windshield Making Car Pillars Appear Transparent

Buzz60 (Dec. 17, 2014) Jaguar unveils a virtual 360 degree windshield that may be the most futuristic automotive development yet. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Researchers Bring Player Pianos Back to Life

Researchers Bring Player Pianos Back to Life

AP (Dec. 17, 2014) Stanford University wants to unlock the secrets of the player piano. Researchers are restoring and studying self-playing pianos and the music rolls that recorded major composers performing their own work. (Dec. 17) Video provided by AP
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