Etching

What is the phenomenon called in which the etch rate decreases as patterns become narrower and deeper?

  1. AAutodoping
  2. BAspect-ratio-dependent etching (ARDE, microloading)
  3. CDishing
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Answer: B. Aspect-ratio-dependent etching (ARDE, microloading)

Ions and radicals have difficulty reaching the bottom of narrow, deep holes, and reaction products are hard to remove, so the higher the aspect ratio, the slower the etch rate. This is called ARDE or the microloading effect, and it causes depths to vary with pattern dimensions.

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More Etching questions

  1. Which gases are commonly used for dry etching of polysilicon gates?
  2. What is the process called that removes photoresist by oxidizing it to ash with oxygen plasma or similar?
  3. Which is a characteristic of atomic layer etching (ALE)?
  4. Which correctly describes one mechanism by which dry etching achieves anisotropy?
  5. Which solution is commonly used for wet etching of silicon nitride?