Simulation of air bubble scattering effects in 193 nm immersion interferometric lithography
Resource
Journal of Vacuum Science & Technology B 23 (6): 2684-2693
Journal
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Journal Volume
23
Journal Issue
6
Pages
2684-2693
Date Issued
2005
Date
2005
Author(s)
Lin, C. H.
Abstract
In 193 nm immersion lithography, the presence of air bubbles in water poses a serious concern to the resist image formation. In this study, air bubble scattering effects were characterized by the Mie theory and the finite-difference time-domain (FDTD) method. The influence range of bubbles both in forward and lateral directions with respect to their sizes was analyzed. It is predicted that as bubble size exceeds 90 nm in diameter, light scattering becomes significant. In the FDTD simulation, the effects of scattered waves in two- and three-beam interferometric lithography were simulated to mimic the actual imaging formation in an immersion scanner. It is found that the more beams are involved in the image formation, the more scattered waves interfere with the image forming waves, and then degrade the final image. Finally, the effect of a moving bubble was also simulated. The phenomenon of image distortion in the presence of bubbles was simulated by employing the three-dimensional FDTD method. © 2005 American Vacuum Society.
SDGs
Other Subjects
Computer simulation; Finite difference method; Image processing; Interferometry; Lithography; Image distortion; Image forming waves; Mie theory; Bubbles (in fluids)
Type
journal article
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