Why Are Parylene Coatings Increasingly Being Used?

1. Why Are Parylene Coatings Increasingly Being Used? Parylene is an acronym for Poly-para-xylylenes. The material forms a plastic film when it is applied in a vacuum like gas to target surfaces. The most common types of parylene are Parylene N and Parylene C. It is applied at the room temperature with specialized equipment that permits the control of the coating rate and thickness. The deposition takes place at the molecular level as the chemical, in a dimer form is first converted into a gas under vacuum and heat. It is then pyrolyzed and is deposited finally as a clear polymer film. The material is applied at the rates of 200 microns per hour. Coating of parylene thickness from 0.1 to 76 microns can be applied in the single operation. Parylene has superior coating properties. Due to these reasons, parylene applications have become more routine. They have expanded from the printed-circuit boards to a broad range of industrial, medical and electronic usage. Typical coating for circuit boards is 5 to 20 microns. For silicone and rubber components are applied in the 1-micron range. The Parylene System It offers the advantage of the coatings that are formed from a gaseous phase with an intermediate liquid stage. The particular coating process results in conformal coatings that cover sharp edges, points, crevices, and the other internal surfaces in a very uniform way that has no pinholes. These coatings are gaining in popularity it is important to get the correct parylene thickness. If the parylene is too little, it may mean incomplete coverage, pinholes, and reduced wear ratings. Excess of parylene can reduce the device performance and may lead to wastages as well. The proper thickness measurement helps in maximizing the benefits of parylene coatings. With it, the coating becomes more reliable, light-weight, transparent and biocompatible. Commonly Available Systems For Measuring Thickness Some of the systems available in the market are designed to measure the parylene thickness on the flat surfaces. The easily accessible options are available for parylene thickness measurement on the curved surfaces. They usually extend beyond the standard thickness range of 0.25-75 microns.

2. Summary It is used whenever a thin coating is desired and it: Is pinhole free Is insulated from electricity effects The Parylene will conform to any surface that will not outgas in any environment, no matter what the geometry is.