Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Almost Only Counts in Horseshoes - and Computer Chips

23.02.2005


Professor Melvin Breuer holds a tray of defective chips, part of a batch of 1000 donated by a manufacturer. The specially configured computer behind him allows the chips to be use-tested without being soldered into a board. Breuer is devising new test algorithms that will be able to identify potentially usable defective chips accurately.


Flawed Hardware Can Function Well in Many Applications, USC Researchers Find

Computer chip manufacturers traditionally have had a single, simple standard for their product: perfection. But a USC engineer who has spent his career devising ways to have chips test themselves has found that less than perfect is sometimes good enough — possibly good enough to save billions of dollars. "Chips with any flaws at all have always been discarded," said Melvin A. Breuer, a professor in the University of Southern California Viterbi School of Engineering’s Department of Electrical Engineering. "And this significantly increases the cost for the good ones."

When manufacturers start making a complex chip, a very large percentage are faulty, Breuer explained. The percentage goes down as manufacturing techniques improve, he added, but "by the time the technique is thoroughly mastered, the chip is on its way to being obsolete." Some chip designers try to cut the losses by designing redundancy into the circuits, so that when circuitry fails, other circuitry can take its place. Even with these measures (and they have costs), large numbers of chips wind up as extremely expensive industrial waste.



Traditionally, the wastage — often half the output or more — is written off as a business cost. But are all faulty chips useless? Seven years ago, Breuer and Viterbi School colleague S. K. Gupta began investigating the idea of acceptable errors produced by defective chips. For some applications — security, and accounting and scientific application — errors are intolerable, says Breuer. But for many others, including graphics, there is a surprising amount of leeway for "error tolerance." "If you have an application where the end user is a person, rather than another computer, small changes in the output are imperceptible, " says the researcher, giving as an example images created by a chip with a few defects, in which one or two pixels were out of place.

The critical factor, Breuer says, was being able to cost-efficiently test and accurately predict if a defective chip will provide acceptable performance without having to plug it into the application. Breuer and Gupta have developed simple built-in test structures for chips that can automatically determine attributes regarding their erroneous performance, such as error rate and significance. Breuer specializes in problems like these: He is the author of several books on the subject (including Diagnosis and Reliable Design of Digital Systems and Digital System Testing and Testable Design); and is on the editorial board of the Journal of Electronic Testing.

In a 2004 paper in IEEE Design and Test Magazine, Breuer, Gupta, and Intel Corp. Senior Staff Engineer T.M. Mak were able to set forth a framework to analyze errors and predict usability. One such analysis indicated that 60 percent of chips with a single defect would nevertheless be able to decode MPEG video files and play them back with no user-noticeable errors. Because of this and other work, the National Science Foundation recently awarded $1.1 million to Breuer, Gupta and two other Viterbi School researchers, Antonio Ortega and Keith Chugg, to investigate and develop error tolerance. Breuer and Gupta have also received funding for this work from the Semiconductor Research Corporation, and Breuer has received addition funding from the Okawa Foundation.

Ortega and his students in the Signal and Image Processing Institute within the USC Viterbi School have already created simulations of images produced by flawed chips implementing JPEG and MPEG encoding operations, and the results confirm that a significant fraction of flawed chips result in slightly degraded performance that is unrecognized by the viewer. This group is also looking into additional applications for imperfect hardware.

Chugg and his students in the USC Viterbi School Communication Sciences Institute have demonstrated that turbo decoding chips, which are being adopted for next generation wireless communication systems, are very robust to circuit defects. In fact, such chips can have a significant number of defects in the memory circuitry with little or no perceptible degradation in performance.

Industry is also starting to prick up its ears, says Breuer. "When I first started talking to them," he recalls, "they were very negative. ’We don’t want our name associated in any way with defective product,’ was their response." But their attitude seems to be changing, Breuer says that over the last 12 months he has been invited to give “keynote” talks at three conferences on the subject of error tolerance. “If these ideas catch on, we will see a major paradigm shift in the way chips are designed, tested and marketed. And these ideas will allow industry to continue to scale technology according to Moore’s law, while reducing the cost of chips to the end user,” Breuer notes. He adds that "considering that the net revenues of chips sold in 2004 was over $210 billion, the annual economic impact of these ideas could easily amount to billions of dollars."

Mak, Breuer’s co-author on the 2004 paper, admits he was skeptical at first, with skepticism growing out of earlier experience, with chips combining two functions. “If one of the elements of the chip didn’t work, we thought, we could still use the other.” But Mak said this created logistical problems because the supply of half-usable chips was so unpredictable. He ended up shipping many chips that had no defects to customers who were paying a lower price for the imperfect chips. However, he said, ss trends in chip manufacturing led to denser and denser architectures producing more and more defects, it is becaming increasingly difficult to ship chips, (or even half-chips) that meet the perfection standard.

Mak said that Breuer’s approach held out the promise that an elegant and workable solution might be possible for the logistical problems experienced before. “I’m eager to see what he comes up with,” Mak said. As a further indication of interests in these ideas, one chip manufacturer has given the USC Viterbi School a batch of 1000 defective chips for analysis and testing of usability-prediction algorithms. "We don’t have people going through chip manufacturer’s dumpsters yet, looking for usable silicon, but we’ve just started working," Breuer says.

Eric Mankin | EurekAlert!
Further information:
http://www.usc.edu

More articles from Power and Electrical Engineering:

nachricht Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>