What is Parylene?
Parylene is a common generic name for Poly-para-xylylenes. This material basically forms a plastic film when applied in a vacuum as a gas to target surfaces. The two most common types of parylene are referred to as: Parylene N and Parylene C Parylene is applied at room temperature with specialized vacuum deposition equipment that permits control of the coating rate and thickness. The deposition process takes place at the molecular level as the chemical, in a dimer form, is first converted into a gas under vacuum and heat; then pyrolized to cleave the dimer; and finally deposited as a clear polymer film. The material is applied at rates of 200 microns per hour. Coating thicknesses from 0.1 to 76 microns can be applied in a single operation. Typical coating thickness for circuit boards is 5 to 20 microns. For silicone and rubber components, much parylene coatings are applied in the 1 micron range.
