Lithography

Which correctly describes 'High-NA EUV', developed as the next-generation EUV exposure tool?

  1. AThe numerical aperture of the projection optics was increased from 0.33 to 0.55 to improve resolution
  2. BThe exposure wavelength was lengthened to 193 nm
  3. CIt exposes without a mask
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Answer: A. The numerical aperture of the projection optics was increased from 0.33 to 0.55 to improve resolution

Conventional EUV tools have an NA of 0.33; High-NA EUV raises it to 0.55 for even higher resolution, at the same 13.5 nm wavelength. On the other hand, depth of focus becomes shallower and the exposure field is half the conventional size, among other constraints.

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More Lithography questions

  1. Which metric describes nanometer-scale roughness on the sidewalls of fine resist patterns?
  2. Which correctly describes the factor k1 in the resolution formula R = k1 × λ / NA?
  3. What is the main cause of the stochastic fluctuations that are a problem in EUV lithography?
  4. Why are defects buried inside the multilayer of an EUV mask a problem?
  5. What is the range of exposure dose and focus over which pattern dimensions stay within tolerance called?