Lithography

Why are defects buried inside the multilayer of an EUV mask a problem?

  1. ABecause they make the mask heavier
  2. BBecause they disturb the phase or intensity of reflected light and are printed as pattern defects on the wafer
  3. CBecause they change the mask's color
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Answer: B. Because they disturb the phase or intensity of reflected light and are printed as pattern defects on the wafer

Tiny bumps or particles in or under the multilayer of an EUV mask disturb the multilayer stack and change the phase and intensity of reflected light, which are printed on the wafer as defects. Because they are hard to find from the surface, dedicated inspection tools using EUV light have been developed.

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More Lithography questions

  1. What is the range of exposure dose and focus over which pattern dimensions stay within tolerance called?
  2. In LELE (litho-etch-litho-etch) double patterning, what is especially strictly required?
  3. What is the wavelength of the mercury lamp's i-line?
  4. Which technique illuminates the mask from oblique directions to improve the resolution of fine patterns?
  5. Which method develops a positive chemically amplified resist with an organic solvent, dissolving the unexposed areas?