What is airborne molecular contamination (AMC) in a cleanroom?

AMC (Airborne Molecular Contamination) refers to gaseous chemical contamination in cleanroom air that can affect the manufacture of ultra-sensitive components such as semiconductors, aerospace components and sterile medicines. These contaminants include acids, bases, amines and condensable or refractory volatile organic compounds. At levels sometimes below pptV, they can cause critical defects in photolithography and other manufacturing processes.