The Parylene material

Co-authors and contributors

Parylene is the trade name for a variety of chemical vapor deposited poly(p-xylylene) polymers used as moisture and dielectric barriers.Parylene is a conformal coating that is deposited as a gas in a vacuum chamber. Parylene is a dry process compared to the standard “wet” liquid conformal coatings.

It is a completely different process to the liquid conformal coatings and its properties offer advantages and disadvantages in comparison.

Since it is deposited as a gas its thickness is uniform across the circuit board.

It is the only truly “conformal” coating and this uniformity offers advantages in protection.

It has other unique properties that make Parylene a very interesting material in many applications.

For example, it is possible to routinely waterproof a circuit board using Parylene whereas with a liquid coating, the process can be far more difficult.

The international symbol for Parylene as a conformal coating is XY.

Watch how Parylene is applied.