Tag silicon

Debugging a New Chip

Updated (9:05 p.m.)*

I’m working on an article about a process called post-silicon debugging, something that chip makers like Intel use to catch problems in chips before they ship them out to computer makers. The goal is to find the sort of bugs that only crop up when a chip is put through the wringer. The wringer, in this case, is a setup that injects electricity into a microprocessor to simulate instructions like spell checking a document. Sounds simple enough, right? Well, not really. The picture below is a testing station for the post-silicon debugging process.

Credit: J. Stinson, Intel

*Update: Thanks to Joel Johnson of Gizmodo, this post has found a large (and informed!) audience. Some background on this picture: I got it from a Stanford researcher, Subhasish Mitra, who got it from Intel. It’s not the focus of my piece, so at the time of posting, I didn’t have a lot of information about the specifics. But since it went up some well-informed folks have chimed in (see comments).

In particular, I heard from John Cloudman, an engineering manager at Intel who has worked in post-silicon debugging. This is what he says about the image:

You have a picture of something called a logic analyzer, which is used to monitor what all the external interfaces of an integrated circuit are doing over time, since the signals are too fast or too broad to be observed with something like an oscilloscope.  The Wikipedia description over a logic analyzer is actually pretty accurate: http://en.wikipedia.org/wiki/Logic_analyzer.  Generally, if one is debugging with a logic analyzer setup like this, the processor is running an operating system under relatively normal operating conditions – normal voltage, temperature, frequency.  It would be a relatively rare case to need this complex a setup.

Bringing Stretchable Silicon to Market

When I interview researchers about their projects, I usually ask for a product timeline. It’s not an entirely fair question because researchers rarely have much control over commercialization. It’s a boring question too because they usually answer, “three to five years.”  Still, I like to include these estimates in my stories to keep readers, many of whom aren’t familiar with R&D and product timelines, from getting too excited about the prospect of something like a quantum computer appearing under the Christmas tree.

Given the gap between research and commercialization, I’m excited to give an update on research I first covered in early 2006. A startup called MC10, based in Waltham, MA, will be making products from stretchable, single-crystalline silicon, the high-quality stuff that’s used in computer chips, within the next 18 months.

The great thing about stretchable single-crystalline silicon is that it can do anything chips can do now–sensing, processing, communicating–but it can do it in unusual shapes. Imagine a surgeon’s gloves that read a patient’s pH, a sheet of high-quality electrodes that can conform around the brain of a person with epilepsy, and a camera chip in the shape of an eye. Stretchable silicon can make these things happen.

There are other sorts of flexible electronics, but they are generally made of organic materials, which are printed or painted on flexible substrates. Organic electronics are easy to make, but aren’t as fast as silicon electronics.

MC10 is commercializing work from John Rogers’ group* at the University of Illinois. I wrote a story for Technology Review about the proof of principle: silicon becomes stretchy when it is thinned and cut into ribbons. These ribbons are then adhered to a rubber-like substrate that’s pre-stretched. When the rubber relaxes, the silicon forms waves, but does not crack. The rubber can be stretched and relaxed many times without degrading the silicon. Rogers showed the electrical properties of this wavy silicon are just as good as silicon on a rigid substrate.

stretchable silicon

Since this initial research, the group has made a number of working devices that can conform to different form factors and unusual shapes. David Icke, the head of MC10, gave a presentation at Printed Electronics 2009 on Thursday in which he provided an overview of stretchable silicon applications.

One project that the company will focus on is making skin for robots that perceives distance and senses pressure. Computer vision from cameras can get a robot hand only so far, Icke said. When it gets close to an object, it needs to adjust at a fine scale. Likewise, when a robot hand grabs an object, it needs to know the pressure it’s applying at all contact points. No one wants to be crushed between robot fingers.

After the talk, I caught up with Icke to ask exactly how they are adding perception to robot hands**. He says they’re building infrared emitters and sensors into a stretchable sheet that can be stretched over a robotic hand. The sensors pick up infrared light that’s scattered when it hits an object.

The early products, Icke says, will most likely be high-margin and low-volume. In other words, the company will focus on specialized gadgets, built for a specific customer, like spherical cameras for the U.S. military. So even though stretchable silicon products are on their way, it’ll be a while before you and I can get our hands on them.

*Rogers is a really nice guy, and one of the better science communicators I’ve ever come across. Rightfully, he was awarded a MacArthur Fellowship this year.

**Another way to add perception to a robot hand is being explored at Intel by Josh Smith. He’s built a robotic hand that detects an electric field, which is useful when in proximity to conducting materials like bottles of water or a human body. See a video here.

Exaflops on Beams of Light

A colleague of mine, Katie Bourzac, has written a post about the future of supercomputing according to IBM. Yes, the future is light. Essentially, the only way to find enough bandwidth to transport all the data required for future supercomputers is to use photons in waveguides, not electrons in wires.

The problem, however, is that it’s far to expensive to stick today’s lasers, detectors, modulators, amplifiers, etc. into computers. These devices are used to send data through the optical fiber that connects the world to the Web, but they are made of materials that are relatively expensive like indium gallium arsenide and others. There’s good news, though, for those who love supercomputers (and really, even if you don’t know you do, you totally do): there are a number of companies, including IBM and Intel, that are looking at using silicon–the same material found in electronics everywhere– for photonic devices.

If you know anything about bandgaps and optical properties of materials, you know that using silicon for photonics sounds a little crazy, but within the past five years, researchers have come up with engineering work-arounds that have made silicon feasible . And because silicon is at the heart of the electronics industry, and there’s a whole manufacturing infrastructure built around it, huge quantities of electronics can be churned out relatively quickly. Soon, photonic devices made of silicon could be churned out just as fast, and at such volume that their prices plummet. That’s when they can be integrated into computers and eventually chips.

It’ll take some time–some say at least a decade–but the gears have already been set in motion. Intel, for example, is pushing its photonics research into the market.  The company recently announced Light Peak, an optical cable that attaches a personal computer to peripherals, shuttling data at 10 gigabits per second. The first versions will contain old-school optics made with expensive materials. But Mario Paniccia, head of Intel’s Photonics Technology Lab hopes that Light Peak will be the Trojan horse to get photonics into the electronics industry; future versions will likely use silicon photonic parts.

Silicon photonics is a topic I’ve covered extensively for Technology Review. For the curious, here’s a link. I’ll continue to follow the work in the field because, from what I’ve seen, it’s the only way to keep pushing computation speeds. Also, it’s just so nerdy cool.

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