Deposition (CVD and PVD)

Which correctly describes uses of silicon nitride (Si3N4) films?

  1. AAs the main material for gate electrodes and wiring
  2. BAs the oxidation mask for LOCOS, the CMP stop layer, and the surface protective film (passivation)
  3. CAs a substitute for photoresist
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Answer: B. As the oxidation mask for LOCOS, the CMP stop layer, and the surface protective film (passivation)

Silicon nitride resists the passage of oxygen and moisture and is hard, so it is used as the mask for local oxidation (LOCOS), the CMP stop layer in STI formation, and passivation that protects the chip surface from moisture and mobile ions. It is also used as an etch stop and hard mask.

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More Deposition (CVD and PVD) questions

  1. What is the main purpose of placing magnets behind the target in magnetron sputtering?
  2. Under what condition does CVD give good step coverage (conformality)?
  3. When silicon films are deposited by thermally decomposing silane, what kind of film forms if the deposition temperature is lowered?
  4. Which is an example of a typical material deposited by ALD?
  5. What is the main purpose of a sputtering method that ionizes sputtered atoms and draws them vertically onto the wafer with a bias?