Etching

Which is a general characteristic of wet etching?

  1. AIt is highly anisotropic because it uses plasma
  2. BIt generally proceeds isotropically and readily undercuts the mask
  3. CIt requires vacuum equipment
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Answer: B. It generally proceeds isotropically and readily undercuts the mask

Wet etching dissolves films by chemical reaction with solutions, so it generally proceeds equally in all directions (isotropic) and undercuts the mask (side etch). The equipment is simple and high selectivity is easy to achieve, but dry etching is used to pattern fine features.

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More Etching questions

  1. Which correctly describes reactive ion etching (RIE)?
  2. Which method is commonly used to detect the endpoint of dry etching?
  3. What is the aspect ratio of a hole or trench formed by etching?
  4. What is the phenomenon called in which the etch rate decreases as patterns become narrower and deeper?
  5. Which gases are commonly used for dry etching of polysilicon gates?