Journal of the Optical Society of America. A, Optics, image science, and vision
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J Opt Soc Am A Opt Image Sci Vis · Jun 2007
Influence of the mask magnification on imaging in hyper-NA lithography.
Argon fluoride laser (ArF) lithography using immersion technology has the potential to extend the application of optical lithography to 45 nm half-pitch and possibly beyond. By keeping the same 4x magnification factor, the dimensions of the structures on masks are becoming comparable to the exposure wavelength or even smaller. The polarization effect induced by mask features is, however, an issue. ⋯ The near-field intensity and phase distributions from the mask are calculated. The imaging performance of 4x and 8x masks for the sub-45 nm node are explored. A rigorous coupled-wave analysis is developed and employed to analyze the optical diffraction from the 3D topographic periodic features.