SAN JOSE, Calif. At the SPIE Microlithography conference here on Monday (Feb. 20), IBM Corp. said that it has created the world’s smallest line patterns using 193-nm optical lithography.
Using 193-nm immersion techniques, IBM claims to have made distinct and uniformly spaced ridges at only 29.9-nm wide. This is less than one-third the size of the 90-nm features now in mass production and below the 32-nm level that the industry consensus held as the limit for optical lithography techniques, according to IBM.
"Our goal is to push optical lithography as far as we can so the industry does not have to move to any expensive alternatives until absolutely necessary," said Robert Allen, manager of lithography materials at IBM's Almaden Research Center, in a statement. "This result is the strongest evidence to date that the industry may have at least seven years of breathing room before any radical changes in chip-making techniques would be needed."
When light passes through a transparent material, it slows down in proportion to the material's "refractive index." Light passing through a higher-index material has a shorter wavelength and can thus be focused more tightly. Resolution in immersion lithography is limited by the lowest refractive index of the final lens, fluid and photoresist materials.
In IBM's NEMO experiments, the lens and fluid had indices of about 1.6, and the photoresist's index of refraction was 1.7. Future research is aimed at developing lens, fluid and photoresist materials with indices of refraction of 1.9, which would enable even smaller features to be imaged.
IBM reportedly used a 193-nm immersion scanner from ASML Holding NV. The record-small pattern of 29.9-nm lines and spaces was created on a lithography test apparatus designed and built at IBM Almaden, using new materials developed by its collaborator, JSR Micro (Sunnyvale, Calif. The first technical details will be presented this week at the SPIE Microlithography 2006 conference being held here.
"We believe that high-index liquid imaging will enable the extension of today's optical lithography through the 45- and 32-nanometer technology nodes," said Mark Slezak, technical manager of JSR Micro Inc. "Our industry faces tough questions about which lithography technology will allow us to be successful below 32 nanometers. This new result gives us another data point favoring the continuation of optical immersion lithography."
Beating its rivals to the punch, Japan’s Nikon Corp. recently claimed to have shipped the world’s first production quality immersion lithography system in the market. The first tool has been reportedly shipped to Toshiba Corp., sources said.