Lithography

What is the role of the thin membrane (pellicle) stretched over a photomask at a fixed distance?

  1. ATo double the resolution
  2. BTo increase the exposure light
  3. CTo keep particles from landing directly on the mask, so that particles on the pellicle are out of focus and unlikely to print
Show answer and explanation

Answer: C. To keep particles from landing directly on the mask, so that particles on the pellicle are out of focus and unlikely to print

A particle on the mask would be printed in every shot on every wafer. A pellicle is a transparent membrane stretched a short distance from the mask; particles land on it instead, are out of focus, and are unlikely to print on the wafer. Special pellicles that transmit EUV light have been developed for EUV.

Practice this topic Back to topic

More Lithography questions

  1. What is the main purpose of the bottom anti-reflective coating (BARC) applied under resist?
  2. Which correctly describes 'High-NA EUV', developed as the next-generation EUV exposure tool?
  3. Which metric describes nanometer-scale roughness on the sidewalls of fine resist patterns?
  4. Which correctly describes the factor k1 in the resolution formula R = k1 × λ / NA?
  5. What is the main cause of the stochastic fluctuations that are a problem in EUV lithography?