Copper chip age coming

Semiconductor manufacturing equipment maker Applied Materials today announced that it is working with semiconductor trade group Sematech to refine the polishing process for the production of chips that use copper to connect circuits. And later this year, IBM is scheduled to release a PowerPC processor based around copper interconnect technology, rather than aluminum, several sources have said.

Copper will likely become the metal of choice for microprocessor circuits as chips get smaller and faster. Copper conducts electricity better than aluminum, the metal traditionally used for circuitry on microprocessors. Copper interconnects therefore allow the chip size to be reduced while speed and complexity is increased.

"If you are shooting for a given clock rate, especially in the 600-plus megahertz range, it is probably going to be easier to get there with copper," said Dean McCarron, principal at Mercury Research.

While copper won't be used broadly for a number of years, manufacturers are already making plans to convert to the metal, said Rob Davenport, director of product marketing in the chemical mechanical polishing division at Applied.

Many are looking to employ copper more broadly with the advent of the 0.13-micron manufacturing process, an ultrafine manufacturing process that's two technology generations from now. This year, manufacturers began releasing chips based on the 0.25-micron process, while next year a select few will introduce 0.18-micron process chips.

"It varies from company to company, but somewhere between the 0.18 and 0.13 [micron manufacturing processes] most logic manufacturers are looking to implement copper," Davenport said. "For DRAM [memory chips] it may not be required, but for logic, and especially for microprocessors, it will be."

Under the Applied-Sematech alliance, the two organizations will essentially seek to develop a fungible standard for the polishing process for copper-based chips. While the polishing phase is but one stage in manufacturing, it presents one of the stiffer challenges for copper-based chips. Copper is polished faster than other elements contained in a semiconductor wafer. As a result, normal polishing procedures can erase copper circuitry.

Applied's Mirra chemical-polishing system gets around this by allowing for multiple polishing steps, he said.

Davenport would not comment on whether Applied and Sematech will cooperate on other copper manufacturing initiatives. Further cooperation seems likely, however. Applied is one of the few U.S.-based semiconductor equipment manufacturers. Similarly, Sematech's members include most of the domestic semiconductor manufacturers. Applied and Sematech are also engaged in a number of initiatives, a spokeswoman said.

In the meantime, IBM is gearing up to release the first copper-based microprocessor for commercial use, said sources close to that company. The chip will be released later this year and be based around the PowerPC architecture.

In March, Apple Computer demonstrated a Power Macintosh running a 400-MHz PowerPC using copper technology.

An Intel spokesman said that the entire semiconductor industry will in all probability convert to copper in the next five to seven years. Intel, however, does not have short-term plans to release copper chips, he added. (Intel is an investor in CNET: The Computer Network.)