Cleanrooms and equipment

Which instrument is used to measure the number and size of fine particles in cleanroom air?

  1. ALight-scattering particle counter
  2. BFour-point probe
  3. CEllipsometer
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Answer: A. Light-scattering particle counter

A light-scattering particle counter shines laser light on sampled air, determining particle size from the intensity of scattered light and counting particles from the number of pulses. It is used to certify cleanroom cleanliness and for routine monitoring.

  • A. Correct. It counts particles by scattered light.
  • B. A four-point probe measures the resistivity of films and wafers.
  • C. An ellipsometer measures thin-film thickness and refractive index.
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More Cleanrooms and equipment questions

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  2. Which statement about the amount of particles shed by cleanroom workers is correct?
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