Secret 3M material is at heart of new superfast chip

When it comes to computer chips, the world has always been flat. Their circuitry is etched onto a thin piece of silicon about the size of your thumbnail.

But that slice of silicon is getting full, and not much more microscopic circuitry can be squeezed onto it, analysts say.

So IBM and 3M have become partners in a new effort to make the chip world three-dimensional. They plan to stack circuitry in high-rise towers on top of computer chips in order to make computing modules that are 1,000 times more powerful than the chips used today in smartphones and other consumer electronics gadgets. This video helps explain the concept.

"You're talking about taking something that would normally sit under a desk being put into a package the size of a thumbnail," said Bernie Meyerson, IBM's vice president of innovation in Yorktown Heights, N.Y. The first thumbnail-sized computer modules are expected to be available in two to five years, he said.

3M, which admittedly is not a computer company, is nonetheless essential to the chip's design. Each layer of silicon circuitry in the "tower" would be separated from its neighbors above and below by layers of a 3M polymer that acts as an adhesive, an electrical insulator and a cooling material to carry away heat. The company declined to provide any details about the new material.

How is it possible to make thumbnail-sized computers? With ultra-thin computer layers. Only the bottom chip in the stack needs to be thick enough to be structurally strong, Meyerson said. The others can be much thinner. As a result, despite its "tower" description, an IBM-3M chip with 100 layers of circuitry stacked on top would not, to the unaided eye, be noticeably thicker than a normal computer chip, he said.

Smallness has its rewards. One of the keys to the IBM-3M package is that its compact size cuts the distance electronic signals must travel from one chip to the other, allowing the chips to run faster and use less electricity.

"So you're saving power and getting tremendous amounts of speed," Meyerson said.

"The fascinating aspect of these chips is that you can put phenomenal capability in a very tiny area," Meyerson said. "But logic chips generate large amounts of heat, and we must get that heat to propagate to the top and sides of the chip to get rid of it. And heat just hates to do that."

Enter the 3M polymer layer, which allows heat to flow through it to get out of the chip. Without that layer, the chip's self-generated heat would cause it to expand and break apart, Meyerson said.

"Without getting into any detail about what's in the 3M polymer, I can tell you that it works because of the linkages between atoms," Meyerson said. "If you can change the way the atoms bond to one another, you can increase or decrease a property of the polymer. This is the miracle of what they do at 3M. It's really magic unless you're a Ph.D in chemistry."

The technology will be watched closely in the competitive semiconductor industry.

"If the 3M-IBM film is truly an electrical insulator and a heat conductor, it is revolutionary, since such materials don't exist in nature and have to be engineered," said Mali Venkatesan, a semiconductor analyst at research firm IDC in San Mateo, Calif. "We have to wait and see the results."