Swing curve measurement and simulation for high NA lithography

In this paper, we will present a new swing curve measurement and simulation method. Swing curve measurements were completed using a high NA KrF Scanner (Nikon S207D) where illumination and reflectance sensors were utilised to measure the reflectivity of the total wafer stack. With this new method, the influence of the full illumination NAill (including effects of polarized illumination and immersion lenses), as well as the substrate properties can be taken into account. A new software has been developed to calculate the swing curve for a film stack of multiple layers on any given substrate, taking into account incident light integration over the whole aperture of the lithography tool objectives. The software also covers diffraction effects and their influences upon the swing. We will demonstrate, that with this new method, even mask diffraction effects can be described allowing a final and more accurate calculation and optimisation of the swing effect.