Airborne Molecular Contamination (AMC) can be a “silent poisoner” of your process and product. AMC is any unwanted organic or inorganic molecule that is carried by the air to the surface of the product. The world of wafer fabrication categorizes AMC as acids, bases, condensables, and dopants.¹ In a more global sense, AMC is productively thought of as any molecule carried by the air that masks or reacts with the surface.

If you are involved in semiconductors, nanodevices, or critical aerospace applications, AMC is an obvious concern. If you are involved in production that does not use a cleanroom, such as engineered coatings or consumeroriented products, consider how controlling AMC can improve your product yield and product performance.

Given the inherent scale of molecules, AMC is neither typically detected by particle monitors nor is it trapped by traditional filtration systems. In terms of airborne contamination, historically, the bulk of attention has been given to particulate contamination, in part probably because it is easier to detect. However, many critical product failures, both immediate and latent, have been traced to AMC.

AMC AND PRODUCT DAMAGE
AMC changes the nature of the surface of the product and therefore its properties. AMC may leave a condensable, non-reactive coating on the surface; in extreme cases, this residue forms a sticky, ointment-like residue. Typically, the residue is an exceedingly thin film that is not visible and is detected through laboratory analysis. AMC residue can prevent adherence of coating or doping material. Or the AMC layer may remain underneath a subsequent desired coating layer and react with either the substrate or the overlying coating. AMC may also contact the surface, react with and modify (damage) the surface, and then volatilize, leaving no detectable residue.