Sunday February 11 3:27 PM ET
High-Tech Copper Seen at Heart of New Microchips
By Zach Howard
NEW YORK (Reuters) - For decades, the world's top microchip makers sought to harness copper's superior electrical conductivity to build microprocessors that were faster, smaller and more efficient than problem-ridden aluminum chips.
Finally, in December, International Business Machines Corp. leaped into production with new technology boasting the smallest copper circuits ever developed and improved materials, allowing for more layers of memory and more processing power.
The groundbreaking development is crucial to driving energy-hungry applications like speech recognition and wireless video in the next generation of electronic devices from computers to cell phones.
IBM's new technology, named CMOS 9S, uses new high-speed transistors -- the on/off switches that act as a chip's brains -- bridged to miles of microscopic copper wiring with circuits as small as 0.13 microns, or nearly 800 times thinner than a human hair.
This allows copper microchips to operate at least 25 to 30 times faster than other chips in production, at speeds in the multi-gigahertz range, chip analyst Fred Zeiber of Pathfinder Research in San Jose, California, told Reuters.
Now IBM's competitors in the semiconductor industry like Motorola Inc., Intel Corp. and Advanced Micro Devices Inc. are scrambling to close IBM's two-to-three-year lead in copper-based chip technology, experts say.
``Practically every major manufacturer is right now either bringing copper into mainstream production or has already done it,'' said Risto Puhakka, an analyst at VLSI Research in San Jose.
Know-How For Copper Wires
In 1997 IBM first unveiled the know-how for using copper wires, rather than the traditional aluminium interconnects, to link transistors in chips, although copper was and is a long way off from displacing aluminium in chips on production lines. ''Three years ago, whole world demand for copper used in semiconductor chips would have fitted into a knapsack, whereas the aluminum that has been used historically in chips, and is still in the majority of chips, is still being shipped by the boat load,'' said Richard Doherty, director of research at Long Island, N.Y. consultant Envisioneering.
At this point, copper's use in the industry is going up at a geometric rate of adoption, quarter by quarter, as other manufacturers tap into it, Doherty said.
Aluminum presented problems as chips evolved into smaller, multi-layered, more complex processors, and the wiring was becoming unreliable.
Increasingly, aluminum circuits were restricting the flow of electrical current, creating signal delay between the millions of transistors inside a chip.
But integrating miniaturized copper with a chip's other components had posed its own set of challenges as copper tended to oxidize easily and its impurities weakened materials around it.
This meant that advances in chip making usually were limited to improvements in transistors, leaving manufacturers stuck with aluminum circuitry.
Latest Breakthrough
IBM's latest breakthrough, CMOS 9S, connects copper with silicon-on-insulator (SOI) transistors and ``low-k dielectric'' insulation, which shields the copper and reduces electrical interference between wires.
SOI is key in enabling fully functional mainstream microprocessors, the most complex type of chip, to run faster, while also requiring less power, which IBM sees extending battery life in the onslaught of small, handheld products that will be pervasive in the future.
For now, CMOS 9S will be driving microprocessors in IBM's high-end Internet ``eServer'', due out this year, and in premium-priced wireless devices and networking gear, now in production at its high-volume manufacturing plant in Burlington, Vermont.
Nintendo (news - web sites) Co.'s new ``Game Cube'', which arrives on shelves this July, also employs a new copper chip.
Apple Computer Inc. had seized upon IBM's copper-based technology as early as 1998 and began shipping those chips in its PowerPC line of personal desktop computers and later in laptops.
A broader range of portable devices should absorb the technology in the next two to three years, said Chris Andrews, a spokesman at IBM Microelectronics.
Andrews said the pursuit of ``integration of function'' is right now a focal point in the industry that will lead to smaller, faster, cheaper to produce products in the marketplace.
``Customers are looking to take multiple chips and combine them into one, so that you have all these separate functions being performed by one chip,'' he explained.
In a Web-enabled cell phone, for example, battery life can be extended by improving chip design. And with other hand-held devices using newer technology, the chip will be the primary enabler of a capability like speech recognition.
Presently, most chips are used not in servers or PCs but as embedded or ``dedicated'' processors in everyday products like coffee makers and clock radios. Computers in the tens of millions of cars shipped each year also are benefiting from advancements in copper chips, ensuring demand stays red-hot, Andrews said.
The transition to different materials in chips which finally jump from the testing phase to production opens the door for new equipment manufacturers to enter the semiconductor industry, explained VLSI's Puhakka.
``The materials are fundamentally different now and copper is at the very heart of this materials transition,'' he added.
In the case of copper, though, its purity must be of the utmost quality, since impurities and heat stress are the most common culprits in chip failure.
The metal will have to be even more refined than exchange-traded, 99.9 percent pure cathode, which currently fetches about 83 cents a lb. on the New York Mercantile Exchange.
But physical demand for the red metal in chips remains small, weighed against other copper consuming sectors like construction or plumbing.
``I don't see warehouses of copper coming here,'' Puhakka said from his Silicon Valley office. ``There is no demand for tons of copper.''
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