INDUSTRY NEWS

SEMATECH WATCH

Deposition breakthrough brings consortium to dawn of the Copper Age

Sematech has entered the Copper Age. The R&D consortium announced in August that it has produced its first copper metallized wafers. Because copper is a better electrical conductor than aluminum is, the technical breakthrough gives the organization's 10 chipmaking members a jump on meeting the goals of the upcoming National Technology Roadmap for Semiconductors.

TESTING ITS METAL: Sematech Engineer Jeniece Pak displays a copper metalized wafer (left) next to a standard aluminum-coated substrate.

According to Jon Dahm, Sematech's director of interconnect, the milestone accelerates "by six months or more" the timeline for making the combination of copper and low-k dielectric process technology available to member companies.

"The next step is to actually integrate the copper deposition piece and the low-k piece to build actual working interconnect structures," says Kenneth Monnig, program director for advanced interconnect. "Our first milestone is [to build] a one-level structure by the end of this year and the next two-level structure roughly by this time next year."

Asked whether that is a realistic timetable, Monnig replies, "It's a push," adding with a slight laugh, "If it was doable we probably wouldn't do it." Putting the technology in the hands of Sematech's member companies will enable them "to develop a suite of technologies they can use to accelerate or spin off their own unique developments."

As for whether the technology poses any contamination problems, Monnig says, "We are going to have to do a study of how much copper is carried along with these wafers into an integrated circuit factory. We have to determine whether you have to build a completely isolated factory or not."

Quite a big decision, no? "In a sense it is; in a sense it isn't," Monnig says. "If you're building a new factory, [it's not an issue]. It's really a question for people who want to retrofit this technology into an existing factory already using aluminum interconnect technology.

"It's also an issue for people who might want to build pilot lines and who share resources with an existing factory. In one sense the interconnect parts of the fab are pretty much segregated from the other processes these days. We are already starting to measure copper levels in a factory that ostensibly doesn't have any copper in it."

Monnig notes that copper "is one of those things people never measured for before," adding that there is a question of whether the metal's presence poses a problem in the first place. "We're at the preliminary stages of measurement. We're doing it essentially on the basis of which tools are going to be shared and which are not going to be shared."

Concludes Monnig: "It's not really well known if you actually put copper in a wafer at certain concentrations what impact it will have on device performance."

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