Estimated impact of shot noise in extreme-ultraviolet lithography

Through simulation we examine the predicted resist images for 50- and 80-nm contacts in the presence of three sources of fluctuations: those associated with random photon absorption sites, those associated with dose statistics, and those associated with resist chemistry. Photon absorption simulations were done using simple optics theory or Monte Carlo techniques. These absorption maps were converted into an initial map of photoacid concentration and a realistic PEB model was used to obtain the developable latent image. A new dissolution model was used to estimate the final resist profile, and image analysis routines were used to extract the centroid position jitter, diameter fluctuations, and edge roughness statistics. The simulations show that each source of fluctuation can be significant, and we propose an experiment that will detect the presence of shot noise and partially separate the three fluctuation sources.