1 January 2004 Image characterization of bubbles in water for 193-nm immersion lithography-far-field approach
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The scattering of bubbles in water by 193-nm light is characterized analytically with Mie scattering theory. The angular-resolved spectra with bubble sizes 100 nm, 1 µm, and 10 µm are calculated. For large bubbles, the forward scattering becomes very strong and therefore introduces a pattern-dependent flare. The normalized cross section with variant bubble size is also calculated. For bubble sizes smaller than the incident wavelength, the cross section decreases steeply and is explained by Rayleigh scattering. A contour plot of the normalized cross section versus the bubble size and the variance of refractive index is also calculated. This plot is explained with the Born approximation and is used to characterize the temperature control of the water during exposure. Finally, a statistical model is suggested to predict the image degradation caused by the phase information loss after the scattering. A bubble density 0.03/µm3 with 1-µm bubble size causes a loss of exposure latitude from 28 to 22%.
© (2004) Society of Photo-Optical Instrumentation Engineers (SPIE)
Tsai-Sheng Gau, Tsai-Sheng Gau, Chun-Kuang Chen, Chun-Kuang Chen, Burn-Jeng Lin, Burn-Jeng Lin, } "Image characterization of bubbles in water for 193-nm immersion lithography-far-field approach," Journal of Micro/Nanolithography, MEMS, and MOEMS 3(1), (1 January 2004). https://doi.org/10.1117/1.1630602 . Submission:


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