Cleanrooms and equipment

Which filter is used to remove airborne molecular contamination (AMC) such as ammonia and organics from cleanroom air?

  1. AULPA filter
  2. BChemical filter (using activated carbon or ion exchangers)
  3. CMetal-mesh prefilter
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Answer: B. Chemical filter (using activated carbon or ion exchangers)

ULPA and HEPA filters capture particles, but gaseous molecules pass through them. Chemical filters use activated carbon, ion exchange resins and the like to remove acid, alkali, organic and other molecules by adsorption or reaction. They are used at outside-air intakes and on critical tools such as exposure systems.

  • A. A ULPA filter captures particles and lets gaseous molecules through.
  • B. Correct. It removes molecular contamination by adsorption or chemical reaction.
  • C. A prefilter removes large dust.
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  1. In cleanroom air conditioning, which unit filters outside air and adjusts its temperature and humidity before supplying it to the recirculating room air?
  2. In a fab's automated material handling system, which automated storage holds FOUPs temporarily until their next process step?
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