Intel drops 157-nm tools from lithography roadmap

Intel drops 157-nm tools from lithography roadmap
SANTA CLARA, Calif. -- Intel Corp. has revised its lithography strategy for the second time in the recent months, disclosing it has dropped 157-nm tools from its roadmap and is not pursuing the scanner technology for IC production. The move is expected to impact fab-tool and material vendors developing 157-nm products for Intel.

Intel originally hoped to deploy both 193- and 157-nm scanners for IC production at the 45-nm node, which is slated for 2007. But now, the company will not deploy 157-nm exposure tools at this node, due to technical problems related to the technology. Lack of lens materials and other issues pose a major problem for the development of 157-nm scanners.

Instead, the microprocessor giant will extend 193-nm scanners for three process technology generations, including the 90-, 65-, and 45-nm nodes, said Peter Silverman, an Intel Fellow and director of the company's lithography capital equipment operations.

"We are continuing on our two-year cycle," Silverman said, referring to the company's aggressive process technology roadmap. "We are changing our lithography roadmap for the 45-nm node," he said in an interview with SBN Thursday.

The move did not surprise analysts, given the ongoing problems with 157-nm tool technology. Nonetheless, Intel earlier this week began to inform its tool and material suppliers about the changes.

At present, Intel has two lithography suppliers--ASML Holding NV of the Netherlands and Nikon Corp. of Japan, sources said. For the 65-nm node, Intel is evaluating scanners from ASML, Canon, and Nikon, according to Silverman.

The litho roadmap shuffle

Today's disclosure represents the latest change in its lithography-tool roadmap. Originally, the company had a straightforward progression in its strategy. It planned to use 193-nm lithography tools for the critical layers at the 90-nm node in 2003, 157-nm tools for the 65-nm node in 2005, and extreme ultraviolet (EUV) for 45-nm in 2007 and beyond.

Then, in February, Intel revised its lithography roadmap, disclosing it will push out the insertion dates of 157-nm and EUV tools due to probable delays with the technologies.

Under that roadmap, there is no change at the 90-nm node. But Intel said it would extend the 193-nm tools down to the 65-nm node, due to technical issues and delays with the 157-nm scanners. Then, Intel was expected to use both 193- and 157-nm tools at 45-nm, but EUV was pushed out due to technical delays (see Feb. 16 story ).

In its new roadmap, which was disclosed today (May 22), Intel plans to deploy 193-nm scanners for three nodes: 90-, 65-, and 45-nm. The primary candidate for the 32-nm node, which is slated for 2009, is EUV, Silverman. "Intel will continue to monitor other potential lithography technologies," he said.

The company has not ruled out using 157-nm tools for the 32-nm node, but the technology is on the outside looking in at Intel. One of the problems with 157-nm tools is obtaining and growing the required calcium-fluoride materials for the lithography lens, Silverman said. "The material is very expensive and the supply is very low," he said.

There are other issues. Photoresists and pellicles for 157-nm tools remain immature--if not non-existent. And researchers found unsuspected high levels of intrinsic birefringence in the lens materials, which will severely affect lens design and images at the wafer level in 157-nm tools.

Roadblocks for 193-nm tools?

There are also several challenges to extend 193-nm tools down to the 65- and 45-nm nodes. "It does add to the challenges," Silverman said. "It requires the technology to work harder."

Lithography vendors are already working on high numerical aperture (NA) 193-nm tools for advanced IC production. But IC vendors must also resort to an assortment of resolution enhancement techniques (RETs) such as OPC, embedded phase shifters, and off-axis illumination, he said.