7 July 1997 Analysis of nonlinear overlay errors by aperture mixing related with pattern asymmetry
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Modified illumination scheme such as off-axis illumination or low partial coherence illumination in combination with phase shift mask is very reliable technique even to the manufacturing stage. In spite of its benefit of drastic improvements in resolution and depth of focus, it has several well known drawbacks. Those are pattern structure dependency, increased proximity effect and significant degradation of illumination power. Furthermore, several studies are reported about the distortion-like registration error between each illumination aperture while various apertures are mix-used. However, the origin of this distortion-like overlay errors is still uncertain and just considered as having some relationship with lens aberration probably, coma. In this study, we investigated the nonlinear character of the registration errors and try to find out the implicit relations of its to the lens aberration character through experiments and simulations.
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Chang-Moon Lim, Chang-Moon Lim, Ki-Sung Kwon, Ki-Sung Kwon, Donggyu Yim, Donggyu Yim, Dong-Hwan Son, Dong-Hwan Son, Hyeong-Soo Kim, Hyeong-Soo Kim, Ki-Ho Baik, Ki-Ho Baik, "Analysis of nonlinear overlay errors by aperture mixing related with pattern asymmetry", Proc. SPIE 3051, Optical Microlithography X, (7 July 1997); doi: 10.1117/12.276014; https://doi.org/10.1117/12.276014


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