While lithography vendors and chip makers are still evaluating immersion lithography for future IC production, the technology could potentially turn the industry upside down. Immersion lithography could potentially extend 193-nm tools down to 45-nm and possibly below--thereby sending 157-nm and extreme ultraviolet (EUV) into oblivion.

In immersion lithography, the space between the projection lens and the wafer is filled with a liquid. For the 193-nm exposure wavelength, water turns out to be the preferred transparent medium. Immersion technology could offer better resolution enhancement over conventional projection lithography because when it is to be in contact with a liquid the lens can be designed with numerical apertures higher than one, which results in being able to produce smaller images.

Chip-making consortium International Sematech recently held a "workshop" on immersion lithography technology and undertook to perform a feasibility study on six-month time-frame. As part of the workshop researchers drew up a top 10 list of challenges facing the promising technology (see Dec. 17, 2002 story ).

Sematech will report its initial finding in mid-2003, but some believe the technology is still an R&D curiosity. It may take until 2008 or 2009 to prove the technology is even viable--if at all, said Peter Silverman, Intel Fellow and director of Intel Corp.'s lithography capital equipment operations. "The technology is more than not ready," he told SBN

Still others believe the technology could turn the lithography industry upside down. The total available market for immersion lithography tools is projected to reach $230 million in 2005, according to The Information Network, a New Tripoli, Penn.-based market research company.

"Currently and in the near future, immersion lithography will be used in niche applications where contact and proximity printers, 1X steppers, and direct-write e-beam tools are currently used," said Robert N. Castellano, president of The Information Network. "That market was $120 million in 2002 and will grow to $230 million in 2005."

"After 2005, immersion tools will have matured to a point whereby they could ostensibly be used as the next-generation tool beyond 193-nm DUV for semiconductor applications, competing with ASML, Canon, and Nikon," added Castellano.

However, ASML, Canon, and Nikon are separately looking into the technology for future development. "If immersion lithography is feasible, post-193-nm lithography will be 193-nm," said Akikazu Tanimoto, general manager of the design management department in the IC Equipment Division at Nikon Corp. of Tokyo.

Immersion lithography could be a major breakthrough "if it is feasible," but the industry is still taking a wait-and-see approach, said Phil Ware, a Fellow at lithography-tool supplier Canon Inc.

William Arnold, chief scientist at ASML Holding NV, agreed. "On immersion, ASML is continually evaluating emerging lithographytechnologies such as EUV, EPL, nanoimprint, and immersion," Arnold said. "At this time, we have not made any decisions about moving forward with immersion," he said.