Parylene - A Technology Proven over Decades of Use
The unique Parylene polymer series was isolated by a research chemist in the late 1940s at the University of Manchester in England. Union Carbide Corporation scientist William Gorham later developed a deposition process to apply the film, and Union Carbide commercialized the material and process. Para Tech Coating, Inc. purchased licensing for this coating process in 1968, and subsequently developed and patented several important enhancements that optimize performance, consistency and reliability of Parylene vacuum deposition coating.

Parylene has become the protective coating of choice for challenging electronics, aerospace and medical applications. Conformal coatings are generally liquid in nature, while Parylene is formed on surfaces from a high purity powder known as a dimer with no liquid stage. The resulting film is thin and conformal, has no pinholes, and resists the effects of organic solvents, inorganic reagents and acids. Parylene serves multiple purposes including electrical insulation, moisture and chemical isolation, mechanical protection, enhanced lubricity, and surface consolidation to avert flaking or dusting.

Special Parylene Features

Surface Conformability
The gaseous nature of the deposition process allows Parylene to penetrate and coat surfaces that are unreachable by liquid coatings, including sharp points, deep cavities and other hard to reach areas.

Unlike liquid coatings, Parylene film conforms closely to surfaces, including edges, flat surfaces, corners and crevices. This thin coating does not stress delicate features.

Low Dielectric Constant
With the dimensions of many electronic devices and components measured at micron levels, signal processing speeds can be compromised by coating materials having relatively high dielectric constants. Parylene has a relatively low dielectric constant, which -- when coupled with its superior moisture barrier characteristics -- can enhance signal processing speeds and help minimize conductor and interlayer capacitance.

Stress Free Application
Parylene polymerization takes place at room temperature, protecting the circuit board or other device being coated from thermal stress. The film does not cure in the conventional sense, and places no mechanical stresses on fragile components.

Optical Clarity
The transparency and clarity of Parylene film leaves surface features and printed nomenclature clearly visible, to the benefit of quality assurance examination. This non-absorption of visible light also makes Parylene suitable for optical uses.

Superior Electrical Insulation
Parylene's superior electrical dielectric properties make it an ideal solution for insulating electronic components with minimal dimensional impact. Dielectric strength of the film is greater than 5,000 volts per mil of coating thickness (See Parylene Specifications and Properites).

Bio-Compatibility
In medical applications, Parylene provides a pinhole-free, inert barrier against moisture, chemicals, bio-fluids and bio-gases. Parylene types N and C comply with the USP's (United States Pharmacopeia's) extensive Class IV biological testing requirements, delivering the high level of bio-compatibility necessary for implants and other long term medical applications (see Parylene Applications).