7 March 2008 Performance of the FPA-7000AS7 1.35 NA immersion exposure system for 45-nm mass production
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Canon has developed an immersion exposure tool, the FPA-7000AS7 (AS7), with the industry's highest NA of 1.35. This paper reports on its performance. The AS7's projection lens achieves ultra-low aberration with total RMS of less than 5 mλ and flare of less than 0.5%. The resolution capability is 37 nm with k1 = 0.259, and DOF of 0.8 μm was obtained owing to the ultra-low aberration and low flare. Regarding focus performance, a 3σ value of 19.3 nm for Lstage and 16.1nm for R-stage were attained in a whole area. The result of CD uniformity of 1.91nm (3σ) was obtained across the wafer with a total of 4032 measurement points. Distortion was 3.9 nm at the worst value. On the other hand the most critical issue of immersion is defects, so the nozzle, lens and stage must be cleaned to reduce defects. The result of defect evaluation of the AS7 was an average of 0.042 defect/cm2 from 25 wafers in a lot and average 0.046 defect count/cm2 from long-term defect evaluation for two months. From these results, we are confident that the AS7 is capable of 45-nm node device production.
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Keiji Yoshimura, Keiji Yoshimura, Hitoshi Nakano, Hitoshi Nakano, Hideo Hata, Hideo Hata, Nobuyoshi Deguchi, Nobuyoshi Deguchi, Masamichi Kobayashi, Masamichi Kobayashi, Takeaki Ebihara, Takeaki Ebihara, Yoshio Kawanobe, Yoshio Kawanobe, Tsuneo Kanda, Tsuneo Kanda, } "Performance of the FPA-7000AS7 1.35 NA immersion exposure system for 45-nm mass production", Proc. SPIE 6924, Optical Microlithography XXI, 69241O (7 March 2008); doi: 10.1117/12.771876; https://doi.org/10.1117/12.771876

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