Etching

If etching proceeds at 100 nm/min for 3 minutes, how much film is removed?

  1. AAbout 3,000 nm
  2. BAbout 33 nm
  3. CAbout 300 nm
Show answer and explanation

Answer: C. About 300 nm

The amount removed is etch rate × time = 100 nm/min × 3 min = 300 nm. In practice, some additional etching is done after the endpoint to account for film thickness variation and the like.

  • A. About 3,000 nm is an order of magnitude too large.
  • B. About 33 nm is 100 divided by 3.
  • C. Correct. 100 × 3 = 300 nm.
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More Etching questions

  1. In wet etching, how does the etch rate generally change when the solution temperature is raised?
  2. In plasma tools such as capacitively coupled ones, what is the phenomenon called in which the wafer-side electrode naturally acquires a negative DC potential that accelerates ions toward the wafer?
  3. What is the masking scheme called that stacks three layers, an organic (carbon) film at the bottom, a silicon-containing middle layer and resist on top, to etch fine patterns deeply?
  4. Which gas can etch silicon isotropically without a plasma, for example to remove sacrificial layers in MEMS?
  5. Which technique gradually thins an exposed resist pattern with plasma to create lines narrower than the exposure limit?