Etching

In wet etching, how does the etch rate generally change when the solution temperature is raised?

  1. AIt does not change
  2. BIt increases
  3. CIt decreases
Show answer and explanation

Answer: B. It increases

Wet etching proceeds by chemical reaction, so raising the temperature generally speeds up the reaction and the etch rate. Solution temperature must therefore be tightly controlled to keep the amount removed stable. Some solutions, such as hot phosphoric acid for nitride, are used at high temperature.

  • A. The etch rate depends strongly on temperature.
  • B. Correct. The reaction speeds up and the etch rate rises.
  • C. Raising the temperature generally speeds up reactions.
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More Etching questions

  1. 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?
  2. 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?
  3. Which gas can etch silicon isotropically without a plasma, for example to remove sacrificial layers in MEMS?
  4. Which technique gradually thins an exposed resist pattern with plasma to create lines narrower than the exposure limit?
  5. In gate electrode etching, what is commonly done to preserve the thin gate insulator underneath?