Parylene Coating Facts: A Quick Review

Parylene coating has been used extensively for applications on sensitive components, circuits, aerospace industry, electronics and medical devices.

The application method uses a vapour deposited plastic that results in an extremely thin yet pin-free isolative coating. Choosing such barriers protects assemblies from standard chemical contaminants like moisture, oxygen and carbon dioxide. The coating is applied in extremely thin layers using a dip, flow, spray method or as recommended by the selected Parylene Coating Supplier in Malaysia.

Parylene coating can be applied to any material. It meets the FDA and USPVI standards for Medical devices. It also provides -

• Low friction
• Ultra-thin application
• Abrasion resistance, etc.

Parylene coatings further -

• Stick well to most surfaces
• Provides a great interior coating
• Strengthens solder joints, wire bonds, etc
• Minimizes ionic conductivity
• The low dielectric constant tolerates high-frequency loadings
• Increases the lifespan of PCB and hence its functionality
• Application is stress-free
• The coating is effective against fungi and a range of solvents

Types of Parylene coatings

Parylene coatings are applied in a gaseous state using a chemical vapour deposition process. These are applied to a variety of components, especially electrical equipment. Opting for this deposition process means an effective coating of crevices, internal areas, etc.

These coatings can be useful for applications in the range of 0.1 -76 microns. This is extremely fine when compared to other alternatives available in the same segment. As a result, it results in achieving -

• A pinhole-free coverage
• High tension strain
• Homogeneous surfaces
• A low dielectric constant
• Electrical insulation
• Thermal stability between -200 to +125 Celcius, etc.

As a result, the coatings bring safety against -

• Acids
• Body fluids
• Caustic products
• Dust and temperature extreme
• Water droplets, etc.

Therefore, these coatings are used extensively by automobile, military, medical, implantable manufacturers, etc.

Each type of parylene coating has distinctive properties and applications like

• Parylene AF4 Polymer

The process of production of Parylene AF4 Polymer is one of the most expensive ones among the Parylene manufacturing processes. It requires a three-step synthesis process and has specific applications. Since it is a PTFE analogue, it brings better oxidative resistance, UV protection, etc.

• Parylene C

This type of coating is used for conformal coating. It is poly-mono choro and para-xylene variety derived from material C. This can be deposited at room temperature using Chemical Vapor Deposition technique.

Type C coatings have an ideal defence against corrosive substances, gases and assembly protection. It is ideal for use in oxygen dominated areas and can last for a decade.b

• Parylene N

Parylene N is a less popular variant and it assumes a linear format. It is extremely crystalline and has a carbon-hydrogen combination with a melting point of 420 Celsius. It also offers good vacuum stability. The higher frequency applications of this are also recommended due to its low dielectric constant and dissipation values.

Both types C and N have a higher deposition rate than other forms of Parylene. These also have lower metal contamination and resistance against chemical corrosion.

• Parylene Type F

This type of coating has a fluorine atom on an aromatic ring that brings low dielectric constant, and thermal stability and thus is recommended for inner layer dielectric (ILD), MEMs and nanotechnology applications.

Dawn Tech is a specialized provider of a unique conformal surface coating. Dawn Tech was established in Malaysia and other parts of the Asia Pacific to provide superior coating technology to customers in the region.