Featured Research

from universities, journals, and other organizations

Silicon As Smooth As Glass: Boon To Computer Chip And Solar Cell Manufacturing

Date:
September 16, 2007
Source:
Fraunhofer-Gesellschaft
Summary:
Without silicon there would be no computer industry since most computer chips consist of this semiconductor material. The same is true for solar cells: They too are predominantly silicon-based. The monocrystals are cut in round slices approximately one millimeter thick, which experts call wafers. Their surfaces must be as smooth as glass; irregularities may only be a few nanometers wide, i.e. less than one ten thousandth of a hair. Therefore, after they have been cut out of a large silicon monocrystal, the wafers must be ground and polished.

A new polishing tool -- here, for optical glass lenses -- employs a piezosensor (dark rectangle) for the first time to measure the pressure with which the grinding elements (speckled) polish.
Credit: Copyright Fraunhofer IFF

Without silicon there would be no computer industry since most computer chips consist of this semiconductor material. The same is true for solar cells: They too are predominantly silicon-based.

The monocrystals are cut in round slices approximately one millimeter thick, which experts call wafers. Their surfaces must be as smooth as glass; irregularities may only be a few nanometers wide, i.e. less than one ten thousandth of a hair. Therefore, after they have been cut out of a large silicon monocrystal, the wafers must be ground and polished.

Until now, whether a surface had become sufficiently smooth was only apparent after polishing. If not, the tool had to be reattached and the process repeated – a time-consuming procedure. Moreover, the tool can easily nick the silicon when it is being attached. When that happens, the expensive material of the entire wafer must be machined until the surface is even again.

Researchers at the Fraunhofer Institute for Factory Operation and Automation IFF in Magdeburg have developed a polishing tool that can constantly control the pressure on a wafer – even during polishing. Its revolutionary feature: Several piezosensors and piezoactors are integrated in the tool.

If it comes across an impurity or a material defect during polishing, it intensifies the tool’s pressure on the surface of the material. The piezosensor compresses somewhat and converts this mechanical pressure into electrical voltage. This in turn signals the actor to change the tool’s pressure on the silicon and remove the uneven spot.

“The primary challenge was integrating the sensors and actors in such a way that the tool’s surface is unaffected and the sensor is nevertheless close enough to the surface being machined,” says Susan Gronwald, project manager at the Fraunhofer IFF. Another advantage: The polishing tool consists of three rings lying inside one another so that a wafer’s edge can be ground with a different pressure than the inside.

The new tool shortens machining time and simplifies the polishing process even for optical glass lenses. “The pressure with which material is machined could not be measured here until now,” says the expert. “Hence, the lenses had to be taken out of the polishing process again and again to inspect the surface with a laser. The final finish grinding was done manually.” The sensor-aided grinding system has been in industrial use for a short time.


Story Source:

The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Fraunhofer-Gesellschaft. "Silicon As Smooth As Glass: Boon To Computer Chip And Solar Cell Manufacturing." ScienceDaily. ScienceDaily, 16 September 2007. <www.sciencedaily.com/releases/2007/09/070909212115.htm>.
Fraunhofer-Gesellschaft. (2007, September 16). Silicon As Smooth As Glass: Boon To Computer Chip And Solar Cell Manufacturing. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2007/09/070909212115.htm
Fraunhofer-Gesellschaft. "Silicon As Smooth As Glass: Boon To Computer Chip And Solar Cell Manufacturing." ScienceDaily. www.sciencedaily.com/releases/2007/09/070909212115.htm (accessed September 20, 2014).

Share This



More Matter & Energy News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
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:
from the past week

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