Paratronix Inc. - Parylene Conformal Coatings

Process

The Parylene process involves several aspects. After proper cleaning, activation and masking, the product to be coated is placed in the deposition chamber. The product will remain at room temperature during the coating process. Dimer is placed in the glass tube opposite end from the deposition chamber in an aluminum foil cup called a "boat". The coating thickness is determined by the volume of dimer placed in the boat.

An end cap is then placed over the tube and the process started. The vaporizer radiant heater cycles on and off with a pressure safety interlock to ensure safe operating limits; the Dimer changes from a solid to a vapor and the molecules move down the tube by virtue of the reduced pressure at the opposite end.

The Dimer now moves into the pyrolysis zone which is at 680 degrees C and the high temperature cleaves the Dimer into two divalent radical monomers. The monomer molecules enter the deposition chamber and re-form as a long chain polymer on all surfaces within the chamber.

Studies show each molecule makes an average of l0,000 collisions and because the short mean free path of the molecule vapor (less than l M.M.) the coating forms slowly and uniformly over surfaces with both sharp edges and deep crevices with no pin holes.

A Cold Trap is used between the deposition chamber and the vacuum pump. The cold trap use is twofold:

It prevents Parylene molecules that have not deposited in the chamber from getting into the vacuum pump.
Prevents oil molecules from "backstreaming" into the deposition chamber.

Est. 1981, celebrating 27 years of parylene coating service

Paratronix Inc., 129 Bank Street, Attleboro, MA 02703-1775.
508-222-8979 Fax: 508-222-8813 Info@Paratronix.com