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PArylene coating
[pary·lene coat·ing] - Parylene is the generic name for the poly-para-xylylenes
Parylene is a conformal protective polymer coating material utilized to uniformly protect any component configuration on such diverse substrates as metal, glass, paper, resin, plastic, ceramic, ferrite and silicon. Because of its unique properties, Parylene conforms to virtually any shape, including sharp edges, crevices, points; or flat and exposed internal surfaces.
U.S. PARYLENE COMPANIES
- Medical Coating [www.medicoating.com]
- Circuit Board Coating [www.circuitcoating.com]
- Parylene Engineering [www.paryleneengineering.com]
| Common Substrates / USES | ||
| Microelectronics Surface Mount Devices Surgical Instruments Fiber Optic Components Probes Pacemakers Heat Exchangers Photoelectric Cells Seals Needles |
Catheters Hybrids Elastomers Trocars Relays Circuit Boards Sensors Power Supplies Semiconductors Stents |
Magnets Metal Components Biomedical devices Cores Keypads Forceps Gaskets Capacitors Bobbins Implants |
Parylene Advantages / Benefits
- MIL-I-46058C, Type XY approved
- FDA approved -- USP XXII, Class VI bio-compatibility rating
- UL listed
- Completely pin-hole free barrier coating
- Fully conformal on any type of surface material or design
- Inert transparent polymer
- Meets NBC requirements (AR70 / AFR80-38 / Navinst 3400.2)
- Barrier to oxygen, moisture, chemicals, solvents, and carbon dioxide
- Thermal mechanically stable between -200ºC and 150ºC
- Extremely high dielectric 5,000 volts per 0.001" minimum
- Excellent adhesion properties
- Low stress coating that does not form sites prone to crack initiation
- Low / minimal impact on package cooling
- Hydrophobic
- Barrier to ionic and moisture species
- Chemical and fungal resistance
- Non-contaminating coating and coating process -- no solvents, catalysts or other by-products are introduced during coating
- Entire process is accomplished at room temperature, alleviating temperature stress on parts
- Particle encapsulation / immobilization
- No outgassing (NASA approved)
- High reliability - Suitable for military or commercial applications
- Light weight - compared to other coatings
- Stress-free coatings - Sensitive circuitry unchanged by coating
- Low coefficient of friction - Use as a dry film lubricant
- Transparency - Thin films can be of optical quality
- Outgassing - Virtually none
- Outstanding barrier - Very low permeability to moisture and gases
- Fungus and bacteria resistance - Excellent
- Mechanical - High tensile and yield strength
- Radiation resistance - Suitable for space applications
EXPANDED PARYLENE DETAILS
Uniform thickness and true conformality - the established process guarantees precise control of thickness and inherent uniformity, especially critical in micro-electronics applications; no bridging, thin-outs, puddlings, run-offs which are common problem with other coating materials. Since it is based on a gas, Parylene can penetrate spaces which typical conventional coatings can not cover: small recesses, crevices and holes and even the edges and the inside spaces of very fine tubes.
Pinhole free - tough coatings as thin as 0.1 microns can be achieved without any voids.
Chemical, fungus and bacteria resistance - Parylene resists attack from exposure to most acids, bases and solvents. It is an excellent inhibitor to the growth of fungus and bacteria.
Superior barrier properties - Parylene provides exceptional corrosion protection from moisture, salt spray, corrosive vapors and other hostile environments. Its water vapor transmission rate has been found to be significantly lower than most conventional coatings. With respect to migrating ionic species, Parylene coatings have been proven to act as barrier to extractable metals which otherwise will contaminate substrates.
Impressive mechanical strength - since it has high tensile and yield strength, Parylene is used for encapsulating microcircuits because it increases the pull strength of wire and lead bonds, face bonded chips and conductor bridges and therefore contributes significantly to device integrity. Since its specific gravity is low, the Parylene layers are typically lighter than most other functional coatings.
High dielectric characteristics - its extremely high dielectric strength combined with its electrical stability in various media provide unique insulating property. The dielectric constant and dielectric losses are low and unaffected by absorption of water vapors. Its volume and surface resistivities are advantageously high because of the purity, low affinity to moisture and in particular its freedom from trace ionic impurities present in conventional coatings.
Thermal stability - Parylene coatings remain stable at continuous temperatures as high as 130 deg.C in air, or 220 deg.C in the absence of oxygen. It has good mechanical properties from -200 to 275 C.
Stress-free - since the polymerization of the film takes place on the substrate surface at room temperature, there is no thermal or mechanical stress introduced during application, hence original performance parameters of coated subjects are basically unaffected.
Particle immobilization - assures circuit integrity, preventing mobility of loose solder, wire particles or other mobile debris left from manufacture. Pressed powder parts, ferrites, ceramics, corrosive metals, glass and epoxy particulates can be positively stabilized.
Dry film lubricant -inherent excellent dry lubricity, as indicated by coefficient of friction measurements make Parylene a valuable asset as a dry film lubricant, particularly as a coating for surgical instruments. Compared to fluoropolymers, Parylene has also the ability to provide wear and abrasion resistance.
Sterilization - due to their thermal and chemical resistance, Parylene coatings can survive the conditions of many common sterilization techniques (e.g. autoclave, radiation, ethylene oxide).
