Etching

Which technique gradually thins an exposed resist pattern with plasma to create lines narrower than the exposure limit?

  1. AResist trimming (slimming)
  2. BReflow
  3. CEdge bead removal
Show answer and explanation

Answer: A. Resist trimming (slimming)

Resist trimming gradually and isotropically etches the resist pattern, for example with oxygen-based plasma, to narrow its line width. It has been used to form gates and similar features narrower than lithography can resolve. Because variation in the amount removed becomes dimensional variation, control is crucial.

  • A. Correct. It thins the resist to make narrow lines.
  • B. Reflow heats a film to make it flow.
  • C. Edge bead removal clears resist from the wafer edge.
Practice this topic Back to topic

More Etching questions

  1. In gate electrode etching, what is commonly done to preserve the thin gate insulator underneath?
  2. When a 1 µm film is etched just down to the underlayer by perfectly isotropic wet etching, roughly how much is etched laterally from the mask edge (undercut)?
  3. Which metric expresses how far the sidewall of an etched hole or trench tilts from vertical?
  4. What is the general effect of adding a little oxygen to fluorine-based etching gas?
  5. In a typical etching plasma, how do the numbers of ions and radicals compare?