Deposition (CVD and PVD)

What is the main purpose of placing magnets behind the target in magnetron sputtering?

  1. ATo cool the target
  2. BTo hold the wafer in place
  3. CTo confine electrons near the target with a magnetic field, raising plasma density and deposition rate
Show answer and explanation

Answer: C. To confine electrons near the target with a magnetic field, raising plasma density and deposition rate

Magnets behind the target create a magnetic field near its surface where electrons stay in spiral motion, promoting ionization of the gas and creating a dense plasma. This gives high deposition rates even at low pressure. Most of today's sputtering tools use this approach.

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More Deposition (CVD and PVD) questions

  1. Under what condition does CVD give good step coverage (conformality)?
  2. When silicon films are deposited by thermally decomposing silane, what kind of film forms if the deposition temperature is lowered?
  3. Which is an example of a typical material deposited by ALD?
  4. What is the main purpose of a sputtering method that ionizes sputtered atoms and draws them vertically onto the wafer with a bias?
  5. In deposition and etching equipment, which mechanism holds the wafer on the stage by electrostatic force?