Nanoimprint Lithography: Plays Well With Others?

As if manufacturing semiconductors wasn't a difficult enough science already, the challenges coming down the pike are exponentially, mind-bogglingly more hairy. No wonder we're seeing more and more cooperation among equipment companies and chipmakers. In addition to common sharing of information at workshops and symposiums, industry players are partnering — even with their direct competitors — like never before.

It has been an amazing feat to watch the development of immersion lithography unfold so quickly these past couple years, in a concentrated effort to get it ready for volume production in time. As Phil Ware, senior fellow of lithography at Canon USA, noted at the Lithography Breakfast Forum during this year's SEMICON West, the list of challenges for immersion lithography keeps changing because problems keep getting successfully addressed. Extensive cooperation has helped to make that progress possible.

EUV lithography is another area that has seen unprecedented cooperation, including pre-competitive partnering of the three major toolmakers — ASML, Nikon and Canon — to create standards the rest of the industry can work toward. The EUV LLC brought together a variety of companies and research labs to get the technology moving.

It has come as somewhat of a surprise to see how closely the players are holding their nanoimprint cards to their chests. Nanoimprint lithography, like immersion lithography, was just added as a possible solution in the latest update of the ITRS. Like EUV lithography, nanoimprint lithography is slated for possible inclusion at the 32 nm node. But, unlike immersion and EUV, nanoimprint is seeing a surprisingly little amount of cooperative effort or standards development.

Researchers began development of nanoimprint lithography, which uses a 1× template to mold structures into a thin polymeric film, in the mid-1990s (see "One on One: A Closer Look at Nanoimprinting," p. 40). Although the technology is moving from academia to industry, it is still in its infancy. The leading toolmakers — Molecular Imprints, Nanonex, EV Group, SUSS MicroTec and Obducat — are still working fairly independently, with little being done to build a viable infrastructure. It is a promising technique that offers refreshing bits of simplicity, but it remains to be seen whether it will be able to summon the critical mass needed to bring it into volume semiconductor manufacturing.

Jörg Kühnholz, market development manager of nanopatterning for SUSS MicroTec, commented, "The whole NIL food chain needs to be established, starting from the commercially available stamps, embossing resin, process control, process time, and cost of manufacturing."

Molecular Imprints looks to be making the most inroads into cooperation with companies along the supply chain. The developer has been working closely on templates with DuPont Photomasks, and has received investment dollars from Lam Research and KLA-Tencor. But don't expect Molecular Imprints to be sharing secrets with its competitors in an effort to build the technology. "In photolithography, they're all singing the same song, and they know what they're supposed to do," said S.V. Sreenivasan, founder and CTO. "But we can't afford to reveal what we've done. It's rich with IP."

The chipmakers are keeping quiet about nanoimprint as well. Doug Resnick of Motorola Labs has been a vocal proponent of the technology, but that does not necessarily mean Freescale Semiconductor has embraced nanoimprinting. In reality, Sreenivasan said that some other customers are even closer to actually using nanoimprint — but, he can't talk about them.

I'm not suggesting the researchers reveal all their secrets just for the good of the community; companies need to be able to maintain whatever edge they can. But nanoimprint lithography is going to have to start seeing more cooperative efforts if it is to be seriously considered for 32 nm production.