Intel designers feel the heat

To dissipate the heat created from the increasing number of transistors packed tightly into each microprocessor, the brains of a computer, Intel's engineers need to solve thermal problems that crop up at many different levels--from the design of semiconductors and manufacturing technology, to devising cooling systems for desktop PCs and corporate computer systems.

Today's leading-edge processors can create heat that is equal to a hot plate, as everyone who has pecked away with a laptop teetering on their thighs is aware. Yet within a decade or so, the power density of state-of-the-art processors based on current chip technology could reach levels comparable to a nuclear reactor or a rocket nozzle, which "gets to be unbearable," says Gelsinger, in a wry understatement.

As the problem continues to heat up, a number of efforts are afoot by the industry to tackle temperature, mainly by finding new materials that isolate the tiny wires on the chip. "Everybody is talking about it, but I haven't seen any good solutions," says Linley Gwennap, founder and principal analyst at the Linley Group, a technology research company in California.

One of the more promising recent advances is International Business Machines Corp.'s silicon-on-insulator (SOI) technology, which can deliver a 30 percent reduction in power consumption. At best, however, the IBM technology could alleviate the problem for only a few years. "It's no panacea," says Gwennap, describing it as a one-time solution.

Although the heat problem affects all processor suppliers, the stakes are higher for Intel than for most of its peers. That explains why Intel this year, even in the midst of slowing PC sales, remains committed to spending $11.7 billion on capital expenditure and research and development. The development of state-of-the-art processors, which can be sold at a premium price, is at the core of the chip concern's business strategy. "Intel has to release faster and faster processors every year, otherwise their business model doesn't work," says Gwennap.

In his role as the chief technology officer of the Intel Microarchitecture Group, Gelsinger's task is to maintain the technological leadership of the world's largest semiconductor maker. In practice, that means upholding Moore's Law, the notion that the number of transistors on a chip doubles every 18 months.

The next giga boundry
While the fastest Pentium 4 processor today, introduced only last week, runs at a clock-speed of 1.7 gigahertz, the chip was designed with much higher frequencies in mind, Gelsinger said in an interview in Taipei. The higher the frequency, measured in gigahertz, the faster a computer can perform big, data-intensive tasks--everything from number-crunching a telephone company's call-record data to processing advanced algorithms for voice recognition.

"Five gigahertz? That's easy," says Gelsinger. "Getting past 10 gigahertz--that is the next big giga boundary. ... That's what we architectured the Pentium 4 for."

Computer users, however, would only be able to reap the benefits of such powerful processors with software designed to take advantage of that processing muscle, while for everyday tasks such as word processing and e-mail the extra performance would bring negligible improvement. Nevertheless, the extra power could make long-promising technologies such as natural speech recognition a reality, allowing users to interact with their machines in a more instinctive fashion.

However, to get there--a feat that will take at least several years and maybe as long as a decade--Intel and others, including the companies that supply the equipment for making chips, need to clear a number of hurdles. Specifically, the industry has to design new equipment for making such powerful semiconductors, develop new materials for chips and devise new cooling systems.

"What I feel the most uncomfortable with now really is the power issue," says Gelsinger, because as greater numbers of devices demand increasing amounts of power, new heat-related problems emerge. "It will always be an issue in mobile devices, and it is becoming an issue in desktops, particularly in small form factors, but even in servers," he says.

In addition to working on chip-level solutions, such as microradiators with tiny fluid reservoirs and channels built into the silicon to dissipate excessive heat, Intel is also looking at developing more advanced cooling systems for computer systems all sizes and forms.

Smaller and hotter
Exacerbating the problem is the industry's relentless drive to build smaller devices. While the current crop of Pentium 4 processors are manufactured on a 0.18-micron process technology, referring to the line widths etched onto the silicon, to reach even higher speeds, much smaller line widths will be required. (A micron is one thousandth of a millimeter.)

"The other thing that happens with transistors as you get to these very fine geometries is that leakage occurs, so that even if it is off it is more on than it used to be and that is a fundamental problem," says Gelsinger, referring to cases where inactive transistors still require electricity.

Transistors are miniature electronic switches that are the basic building blocks of a microprocessor. Within the next 10 years, some two billion transistors could be packed onto each chip, compared with 42 million transistors on a Pentium 4 chip. Such a high transistor count could, for ex-ample, allow for one chip to house all the functions needed for a wireless hand-held communications device, says Gelsinger.

For consumers, this should result in cheaper gadgets with more advanced functions. Digital cameras, for example, could become smaller but still produce higher resolution pictures and could store more of them.

To push the performance envelope further out, ever smaller transistors and finer line widths are needed. The first Pentium 4 processors running at over two gigahertz, scheduled to be introduced in the fourth quarter, will be manufactured on a next-generation 0.13-micron process. And the 10-gigahertz mark, says Gelsinger, will probably require line widths no larger than 0.07 micron.

Whether the world's software developers will be able to keep up with the processing power advances remains a question. Without new software programs, the gigahertz race will become an engineering feat without much practical interest.

Still, the race for speed continues apace, generating power problems and heat headaches that will keep Gelsinger and his peers hard at work for years to come. Already, the Pentium 4 is a power hog. When operating at full power, it takes anywhere from 50 to 60 watts. "It is still using 20 to 25 watts even when it is sitting there idle," he adds.