Axel Zibold, Ulrich Stroeßner, & Andrew Ridley, Carl Zeiss SMS GmbH, Germany, & Vicky Philipsen, Joost Bekaert, & Live van Look, IMEC, Belgium

ABSTRACT

Immersion lithography offers the semiconductor industry an opportunity to extend the current ArF processes to smaller half-pitch nodes before switching to a shorter exposure wavelength. The transition to immersion will require increased attention to the photomask along with new effects influencing the aerial image formation as the numerical apertures (NA) of scanners move up to at least 0.93 and beyond. Feature sizes on the photomask become comparable to, or even smaller than, the wavelength and begin to act like wire grid and/or other types of polarizers, which can lead to potentially serious polarization effects.