Copper strikes gold for IBM

Electronic News, Sept 29, 1997 by Chad Fasca

Fishkill, N.Y.--IBM grabbed headlines last week when the company reported its development of a copper manufacturing process that would enable the company to shrink electronic circuitry to smaller dimensions and fit more logic on a chip, it was said.

As last week unfolded, IBM saw much more to copper than Lincoln head pennies--they saw dollars as Wall Street lifted the company's stock to a Monday, Sept. 22, high of 103-7/8 up 4-6/8 from its 99- 1/4 Friday, Sept. 19 close. By Friday, Sept.26's close, IBM shares dipped to 102-3/4. While most have hailed the announcement as a huge breakthrough in keeping with Moore's Law, some industry members reacted skeptically about the timing and significance of the announcement which came within a week of Intel revealing its flash memory breakthrough.

Called CMOS 7S, IBM's new semiconductor manufacturing process uses copper instead of aluminum to reduce the resistivity in metal layers. The move to copper is regarded by many within the industry as necessary to achieve the design shrinks needed to maintain Moore's Law.

IBM will use the process to build higher-performing, higher-function microprocessors for computer systems, while also allowing electronics manufacturers to create innovative new products that are smaller, lighter and require less power. The company plans to roll out their first set of products, including a high-performance PowerPC microprocessor, and announce OEMs using the new technology by the end of October. The new process will be in volume manufacturing later this year.

"I think the introduction of copper is a revolutionary step in reducing the barriers as it pertains to the wiring. That is a must. We have to remove that barrier in the scaling of CMOS. And basically move the industry beyond the point at which aluminum wiring gets stuck." said Bijan Davari, IBM Fellow and senior manager of logic technology development.

Integrating six layers of metal on a chip, CMOS 7S is the first process technology to use a production copper metalization process, according to IBM. The use of copper is said to enhance the electrical properties of a chip's wiring, yielding significant performance gains. The copper process was developed through a close collaboration between IBM's Research and Microelectronics divisions. The CMOS 7S technology fits dimensions of 0.20 micron (Ldrawn), up to 12 million gates and a 0.12-micron effective channel length (Leff), which IBM claims is the shortest in the industry. Transistors based on the CMOS 7S technology can operate at 1.8 volts, making chips based on the technology well-suited for low power, it was said. Chips produced with CMOS 7S can also support 3,000 I/O connections on a single piece of silicon, something IBM claimed was a necessary compact design characteristic for high-performance devices.

Recently, Sematech reported a breakthrough of its own that came during the week of Aug. 4, that Jon Dahm, director of interconnect at Sematech and a Motorola assignee, thought would pull member companies ahead by as much as a year in the drive to switch to copper interconnects. But he considered the IBM process technology in a much different light. "It's an incredible accomplishment, getting it ready for real, live manufacturing of products for sale," said Mr. Dahm. Asked about Motorola's own R&D of copper technology, speculated to be just as far along as that of IBM, Mr. Dahm responded that it is not the position of Sematech to comment on the unreported technology of its member companies. Following the reports of IBM's copper technology came speculation about the equipment manufacturers used by IBM for its CMOS 7S process. According to an IBM spokesperson, the company would not divulge its suppliers, a practice that IBM has consistently employed. But, the lack of word from IBM did not end speculation as to who would continued on page 70

be leading candidates for involvement. News of IBM's copper process sent Kalispell, Mont.-based, Semitool's shares up Tuesday, Sept. 23, to 26-7/8 from Monday, Sept. 22's 24- 1/4 close. Semitool's share then slipped to 24-3/8 at Friday, Sept. 26's close. Industry analysts expressed strong feelings that CMOS 7S uses Semitool electrochemical deposition equipment. Several analysts considered them to be a leader in copper deposition and a near sure bet. Other companies speculated to be tied up in the IBM technology were Novellus Systems and Applied Materials. This could not be confirmed.

Peter Hanley, Novellus executive VP of sales and marketing, said that the company could not comment on their part, if any, in the CMOS 7S process of IBM. He did acknowledge that the two companies had an ongoing relationship, but Novellus is not allowed by contract to talk about any developments made by the two companies. He said that IBM was a good customer and that Novellus was excited about the announcement. Applied Materials was just as quiet about any involvement they may have in CMOS 7S.

"We have a policy internally that we don't give out customer names. We have been working on copper now for several years," said Sass Somekh, senior VP at Applied Materials. Applied has been developing all the pieces to the copper process puzzle. According to Dr.. Somekh, Applied has developed barrier metalization and a physical vapor deposition (PVD) seed layer that is required for the electroplating. They have already delivered this seed layer system, the Endura system. Dr. Somekh describes it as a combination system involving both a barrier layer and a seed layer.