Airborne Molecular Contamination (AMC)/Gas Phase Filtration (GPF)


Increasingly in controlled environments the presence of molecular levels of contamination in the air is damaging to the process being performed. The requirements in high end semiconductor processes are currently being joined by Hard Disc manufacturing and Life Sciences/Pharmaceutical. In some cases the customers need is so critical that the entire facility is filtered for AMCs but due to the very high cost of this approach it is more common that only the most critical process steps are filtered for AMCs, and this approach involves specialty Fan Filters. Typically 3 steps are involved in the successful implementation of an Airborne Molecular Contamination (AMC) removal program.

  1. Determine the AMC specie(s) that are causing your process the problems you are observing. TES can assist you in sourcing qualified labs to do this work. Geography would play a roll in our referral process to a qualified lab, but typically we would recommend Balasz Labs in Fremont, Ca.
  2. After the species and concentration levels are known then we can involve one of several high end strategic partners we work with to define and specify the actual AMC product, taking into account your desire for removal efficiency, expected life, and price point. At the end of this step we will have a product specified that will remove a guaranteed amount of the species for a guaranteed amount of time. PHD scientists provide all the data and the main deliverable is a chart of expected filter life, and efficiency during that lifetime
  3. Design and deliver a custom FFU product that will deliver AMC and particulate air into the clean space.

Why can’t I just use the FFUs I have at my facility with the AMC filters?

  1. Several factors make it unlikely that any standard FFU will work when adding AMC filtration The fan in the FFU is sized only for the resistance of the HEPA filter/ 30% pleated prefilter combination and the addition of a very restrictive filter such as a high end AMC filter would cause the unit to flow at only a small fraction of it’s normal flow
  2. The AMC filters work based on residence time of the air with the AMC media and since common “construction style” FFUs, like the Envirco MAC-10, have a single fan inlet the flow through an AMC filter would be to high to allow them to work at the high efficiencies they are designed to work at.

TES/Airflotek has a wealth of experience in applying AMC filters to custom applications, and there are a number of hurdles to clear that a less experienced FFU provider will not likely to be familiar with. Subjects like designing filter inlet uniformity so the AMC filters will realize their potential for removal efficiency and life are key to a successful AMC filter application. We maintain strategic partnerships with all the major suppliers of AMC filters who’s products include:American Air Filter’s SAAF media

  1. American Air Filter’s SAAF Media
  2. Camfil’s Gigapleat 
  3. Donaldson’s Broad Spectrum Max and Chemcore
  4. Entegris’s Vaporsorb
  5. Purafil’s GridBlok

Depending on your need to remove AMC from key process steps, we can recommend and provide effective AMC removal with your FFU.

Or, conversely, if you have defined an AMC problem we can design a solution, complete with the AMC filter that will guarantee the result you need..

Please call us with any questions you may have at (510) 656-5333 and ask for Jim or Larry

Why Use an Airborne Molecular Contamination (AMC) Filter? (PDF Presentation)


Chemical Filter Big
PTFE FFU with AMC filter