Lithography method decision by end of year.

The future of lithography should be decided by the end of the year when equipment suppliers will deliver a definitive answer on whether immersion techniques can be made to work in production, according to Belgian research center IMEC. In immersion lithography the numerical aperture of the scanner is increased by placing a high refractive index liquid between the lens and the photoresist, making smaller sub-wavelength feature sizes possible. For the current generation of 193 nm machines, which are good down to 65 nm features without immersion, it has been shown that water is an ideal liquid. Applying immersion could extend the life of this equipment down to the 45 nm node, the point at which 157 nm scanners are scheduled to take over. However, immersion lithography at 193 nm still faces issues. It will require huge, and very expensive, lenses to accommodate numerical apertures greater than one, which may also reduce the field size. INSET: The future of lithography.