Vapor Phase Deposition is a physical method of encapsulation by which the core material (solid) is placed in a coating chamber under high vacuum. The coating is a special dimer that is first vaporized under high vacuum, once under the high vacuum the dimer molecule is "cracked" in a furnace, forming free radicals. The free radicals then move into the coating chamber reforming/polymerizing onto the surface of the core material/substrate forming a good conformal wall.
The parylene process is often used to protect electronic parts from moisture and corrosion.
In 1982 the Ronald T. Dodge Company began utilizing the Parylene process to coat small particles, and in 1985 received their first patent for the microencapsulation of electro- luminescent (ZnS) phosphors.
The first in the series is poly-para-xylylene, a completely linear, highly crystalline material.
Is the same as Parylene N but modified by the substitution of a Cl atom for one of the aromatic H.
Is the same as Parylene N but modified by the substitution of two Cl atom for one of the aromatic H.
Non Conformal Coating