Applied, Lucent to expand single-wafer processing for greater fab flexibility

Applied, Lucent to expand single-wafer processing for greater fab flexibility
By J. Robert Lineback, Semiconductor Business News
May 2, 2000 (8:46 a.m. EST)
URL: http://www.eetimes.com/story/OEG20000502S0001

SANTA CLARA, Calif. -- In an effort to reduce the time it takes to fabricate ICs, Applied Materials Inc. and Lucent Technologies Inc. today launched a partnership to greatly expand the use of single-wafer processing tools in Lucent's next-generation frontend chip-making technologies.

Specifically, the partnership aims to replace batch-wafer furnaces, which have slowly given ground to single-wafer systems--such as rapid-thermal processing (RTP) tools--but continue to be used in advanced chip fabs. During last month's Fourth Annual Fab Management Forum in Grenoble, France, Applied Materials managers argued that the use of single-wafer processing tools across an entire wafer fab would reduce work-in-progress (WIP) by 30%, lowering cost and speeding the time it takes to ship semiconductors to the marketplace.

At issue is whether or not it's feasible for high-speed RTP tools to replace batch-wafer furnaces, which can handle a couple hundred subs trates at a time, but requiring loading and unloading times and taking two to three hours to complete high-temperature cycles. Accuracy in fast-ramp heating and cooling plays on the side of RTP, according to single-wafer processing advocates.

Lucent, based in Murry Hill, N.J., sees a huge potential for cycle-time reduction in wafer fabs with expanded use of RTP and single-wafer processing. "Reducing fab cycle time is a key element of Lucent's business strategy. Replacing long furnace process steps with short single-wafer processes is an obvious place to start," said Gregg S. Higashi, Lucent's technical manager of frontend process development, who initiated this project.

"We estimate that we will be able to ship wafers days earlier by using single-wafer processing," he said. "This could put our products into our customers' hands sooner while also reducing inventory."

Applied offers a range of single-wafer process technologies, including RTP and systems for growing oxide thin films as well as depo sition of silicon nitride and polysilicon thin films. Lucent said it will evaluate process quality and reproducibility, manufacturing cycle time, throughput, and total cost of ownership for potential application in its next-generation chip technology.

Under the program, Lucent will initially evaluate several single-wafer thermal process steps in its pilot line using Applied's RTP in-situ steam generation (ISSG) technology for gate dielectric, shallow trench isolation (STI) liner, pad, and other oxide films. Lucent will also use Applied's RTP Centura for implant and STI anneals, the SiNgen single-wafer LPCVD nitride chamber for spacer and pad nitride applications, and integrated poly and gate-oxidation process chambers for polysilicon deposition of the transistor gate.

"Single-wafer technology is especially important to foundries and to ASIC suppliers like Lucent, who need to reduce development and production cycles to keep up with today's increasing demand for new generations of chips," said Chris Gr onet, vice president and general manager of Applied's Transistor Gate and Substrate Product Groups in Santa Clara. "We expect this concept to become more critical as furnaces continue to cause bottlenecks in the process flow."