Nanoimprint litho makes its mark at SPIE
At the SPIE Microlithography conference in California, vendors rolled out tools that are said to have higher throughput, better alignment and astounding resolution—below 10nm—at price points far below those of optical scanners. Nanoimprint tools sell for as little as $100,000, compared with $18 million to $25 million for the latest 193nm optical machines.
Molecular Imprints Inc. introduced its latest nanoimprint product at SPIE and disclosed plans for a next-generation, high-throughput tool codenamed the i300. Norm Schumaker, MII's president and CEO, said the company is putting the infrastructure in place to propel nanoimprint technology from niche-oriented applications to mainstream chip production. MII is working on dielectric materials with IBM Corp., and the imprint vendor reportedly discussed development of nanoimprint "templates" with Japanese photomask giant Dai Nippon Printing Co. Ltd at SPIE, although Schumaker would not comment on the nature of his discussions with Dai Nippon executives.
Nanonex Corp. also rolled out a nanoimprint machine, including a tool that it claims will support sub-10nm resolution.
Perhaps the most impressive display of nanoimprint technology at SPIE involved German chip equipment vendor Suss MicroTec AG. Hewlett-Packard Co. claimed to have fabricated switching molecular-memory arrays at 65nm, reportedly using Suss' MA-6 mask aligner.
While nanoimprint vendors made impressive claims, analysts noted that the market is in its infancy. Many of the tool shipments have targeted R&D work at universities for niche applications in biotechnology, MEMS and optical, said Carl Mann, U.S. regional sales manager for nanoimprint vendor EV Group Inc.
The market's handful of players will ship a combined 45-60 tools in 2005, up from about 40 in 2004, predicted Ken Mason, president of Encrease Inc., a sales and marketing firm that represents nanoimprint player Obducat Inc. in the United States.
Nanoimprint tools' ability to yield sub-100nm feature sizes with relative ease at prices far below those of optical scanners is not lost on the chip industry. But do not look for nanoimprint in mainstream production for at least another five years, said Sven Hansen, manager of the nanoimprint group at Suss.
Leading-edge chipmakers are keeping a close eye on nanoimprint technology, but infrastructure issues, tool overlay and throughput remain stumbling blocks to adoption.
The technology faces "an uphill battle," said Peter Silverman, a fellow and the director of capital equipment technology strategy for Intel Corp. "It does not have current applications in semiconductor manufacturing."
That is not to say that Intel and other chipmakers are ruling out the technology. Nanoimprint has been put on the International Technology Roadmap for Semiconductors as a next-generation lithography candidate—along with extreme ultraviolet, immersion lithography and maskless technology—for the 32nm node.
Some are confident to say that nanoimprint will find a role in 32nm IC production and beyond. "After optical photolithography, it's going to be organic chemistry," said Charles Schaper, chairman of startup Transfer Devices Inc., a Stanford University spin-off that supplies nanoimprint templates. By organic chemistry, Schaper meant the means and materials required to devise nanoimprint templates or masks. Nanoimprint lithography itself does not use an optical lens, but instead employs ultraviolet and immersion techniques to produce patterns on a wafer.
"If you look at the market, there are a lot of non-silicon applications for nanoimprint," MII's Schumaker said at SPIE. But a viable source of templates, materials and inspection gear must be developed before mainstream chip houses adopt the technology, he said, adding that MII is "working with all the mask houses."
Several imprint lithography techniques, using 1x masks or templates, can be used to transfer nanostructure images onto a polymer layer; these include embossing, stamping and molding. Hot embossing creates 3D nanoscale structures on thin material surfaces via a stamping process.
At SPIE, MII rolled out a tool that is said to offer sub-50nm half-pitch resolution. Based on what the company calls step-and-flash imprint lithography, the Imprio 250 provides sub-10nm alignment and includes an automated wafer-handling mechanism for 300mm substrates. It has an in-liquid alignment and magnification control system for precision overlay. Throughput is five 200mm wafers per hour.
Schumaker hinted that MII's next-generation Imprio 300 would have a tighter overlay and faster throughput.
Nanonex showed a tool that features sub-10nm resolution and an integrated layer-to-layer alignment system. The NX-2500 supports thermal, photocurable and embossing forms of imprint. The machine is based on an air-cushion press (ACP) technology, as opposed to the traditional, solid-plate mechanism. ACP not only enables uniformity over an entire wafer, but also allows precise alignment and extremely fast processing times, said Larry Koecher, chief operating officer for Nanonex.
While MII has its sights set on the IC industry, Nanonex is looking at non-semiconductor applications. The company is selling tools for data storage, optical and related apps, Koecher said.
Obducat, which claims to have the largest installed base of nanoimprint tools, is readying an improved alignment system. The company uses a global exposure system as opposed to a step-and-repeat methodology.
While market activity is taking off, Transfer Devices' Schaper advised the industry to gird for a shakeout. "There will be consolidation," he predicted.
- Mark LaPedus
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