THE PARYLENE CONFORMAL COATING PROCESS
Parylene is a unique class of vacuum deposited polymers that produce high quality, pinhole-free, conformal coatings. There are several Parylene polymers, including Parylene N, Parylene C and Parylene D, each with its own set of material attributes, while providing excellent adhesion to most substrates. These polymers also offer exceptional chemical and corrosion resistance, high dielectric strength, extremely low permeability to moisture and gases, high temperature and UV stability as well as biocompatibility, making Parylene the preferred coating material for various medical, aerospace, military and other industrial coating applications.
The process begins with granular dimer that is weighed out to provide the desired coating film thickness and then heated under vacuum to convert it from a solid to a gas state. The gas is then pyrolized at higher temperature, which cleaves the dimer into a monomeric gas. The monomer is subsequently drawn into the ambient temperature coating chamber where it is vacuum deposited onto the desired substrate surface. Since Parylene is applied in a gas phase, it provides very conformal coatings on all unmasked surfaces, including into surface crevices, far beyond the capabilities of other conformal coating processes such as dip or spray coatings.