Discrete Sources Method for analysis of a light scattering by an air bubble on resist for immersion lithography

The discrete sources method (DSM) is applied to calculate light scattering by a half-spherical bubble in water on a substrate. For the first time an algorithm which allows the near-field calculation on the base of DSM is presented. Such investigations are important in immersion lithography, as the presence of bubbles on a resist surface decreases image quality. On the base of DSM the numerical algorithm of the near-field calculation is realized. Numerical results for the near-field inside the resist for different depths under the surface are presented.