How much smaller can chips go?

13 Aug 2010

Barry Collins investigates how much further chip technology can shrink as miraculous feats of engineering give PC-like power to smartphones

Seven of the finest minds Intel can muster are lined up on stage, ready to take questions from a pack of visibly intimidated European journalists.

These are Intel fellows – the highest rank of technical merit afforded to the company’s engineers – whose CVs are stuffed with PhDs and patents in the places that most people put fillers such as “excellent typing skills” and “interest in badminton”.

Finally, one of the press pack plucks up the courage to ask a question. Is Moore’s Law – Gordon Moore’s legendary prediction that the number of transistors on a processor will double every two years – dead? One or two of the fellows chuckle politely, others are visibly irritated. Almost all are eager to grab the microphone and put the impertinent questioner straight.

One by one, they deliver measured and witty responses. “The number of people predicting the end of Moore’s Law doubles every two years,” quips the Scandinavian Tryggve Fossum, before American fellow Karl Kempf delivers a cutting dénouement. “The first microprocessor had 2,300 transistors, now we have processors with 2.3 billion transistors. That’s Moore’s Law. That’s what we do.”

Indeed, it’s what Intel’s been doing for more than 30 years. Now, the company is preparing to defy the laws of physics to “print” its next generation of chips. Chips so crammed with transistors that the machinery is working with sub-atomic precision to make them.

But when you’re already working with transistors a fraction of the size of a virus cell, how much further can you push the miniaturisation before the plucky journalist’s predicted demise of Moore’s Law comes true?

We’re going to reveal how Intel and other manufacturers overcame the enormous technical barriers that stood in the way of today’s chip technology, and explore the challenges they face in shrinking tomorrow’s chips to 22nm and beyond.

The size of the task

The complexity of a modern processor is almost beyond comprehension. A working 1GHz core on ARM’s latest Cortex A9 processors occupies less than 1.5mm2, using the 65nm production process. To put that into perspective: a nanometre is a billionth of a metre, which means a nanometre is to a tennis ball what a tennis ball is to the planet Earth.

“Microscopic” doesn’t even come close.

Yet, if that sounds impossibly fiddly, Intel’s latest Core processors are built using a 32nm process. While you might just be able to spot one of ARM’s cores with the naked eye, to see one of the 32nm transistors on an Intel chip, you would need to enlarge the processor to beyond the size of a house.

Working at such precision is an enormous challenge for chip manufacturers. As processes are refined every two years to keep Moore’s Law alive, Intel’s engineers are forced to show remarkable levels of ingenuity to keep processors ticking. “The end has been predicted many times, and we have shown this is not the case,” said Intel fellow Jose Maiz. “At least, not yet.”

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