Lithography

Which is a characteristic of chemically amplified resists?

  1. AThey dissolve during development even without exposure
  2. BThey react only to heat, not to light
  3. CAcid generated by exposure acts as a catalyst during the post-exposure bake (PEB), driving the reaction with a small exposure dose
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Answer: C. Acid generated by exposure acts as a catalyst during the post-exposure bake (PEB), driving the reaction with a small exposure dose

In a chemically amplified resist, exposure generates acid from a photoacid generator, and during the post-exposure bake (PEB) the acid catalyzes repeated reactions. Because one photon drives many reactions, sensitivity is high, and these resists are widely used for KrF, ArF and EUV.

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More Lithography questions

  1. What is the typical reduction ratio when today's exposure tools (scanners) project the mask pattern onto the wafer?
  2. Which is a characteristic of scanner-type exposure tools?
  3. Which correctly describes masks used in EUV lithography?
  4. Which is the correct general order of lithography steps?
  5. What is the technique called that transfers a pattern by pressing a mold with fine patterns into resist?