Parylene Coating Blog by Diamond-MT

Sean Horn

Recent Posts

Conformal Coating for Agricultural Lighting

Posted by Sean Horn on Fri, Dec 14, 2018 @ 07:30 AM

Used for food production, indoor gardening/hydroponics, and horticulture, grow lights have both industrial and consumer applications.  Because total illumination intensity diminishes with distance from the point source (grow lightbulbs), production efficiency is enhanced by:

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Tags: parylene for LEDs, LED conformal coating, silicone conformal coating, agricultural lighting coating

A Guide to Parylene Temperatures

Posted by Sean Horn on Fri, Dec 07, 2018 @ 07:30 AM

A specialized chemical vapor deposition (CVD) process attaches conformal coatings composed parylene (XY) to substrates.  CVD uniformly encapsulates all exposed substrate surfaces as a gaseous monomer; completely eliminating wet coatings’ liquid phase and need for post-deposition curing.  Synthesizing in-process, CVD polymerization requires careful monitoring of temperature levels throughout

Beneficial thermal properties of XY protective coatings include reliable performance through an exceptional range of temperatures.  Parylene is available in variety of material formats, prominently Types C, N, F, D and AH-4.  Each has a particular range of properties that determine its optimal uses.  Types C and N exhibit faster deposition rates than other parylenes, making them useful for a wider range of coating functions.  However, operating temperature is a significant determinant of use:  Much depends on chemical composition. 

  • Used more frequently than other XY varietals, Parylene C is a poly-monochoro para-xylene.  It is a carbon-hydrogen combination material, with one chlorine group per repeat-unit on its main-chain phenyl ring.  In oxygen-dominated atmospheres, C conformal films regularly provide reliable assembly security at temperatures of 100° C (212° F/water’s boiling point) for 100,000 hours (approximately 10 years).  C is suggested for use in operating environments reflecting these temperature conditions.  Chemical, corrosive gas, moisture, and vapor permeability remain consistently low.  C generates exceptional vacuum stability, registering only 0.12% total weight-loss (TWL) at 49.4° C/10-6 torr (1 torr = 1/760 SAP (standard atmospheric pressure, 1 mm Hg).   C can also be effective at temperatures below zero, to -165º C.
  • With a completely linear chemical format, Parylene N is the most naturally-occurring of the parylene series.  Used less regularly than Type C, N is highly crystalline; each molecule consists of a carbon-hydrogen combination.  N’s melting point of 420° C is greater than most other XY types.  Vacuum stability is high, registering TWL-levels of 0.30% at 49.4° C, and 10-6 torr.  These properties encourage higher temperature applications.  Compared to other XY varietals, N’s low dielectric constant/dissipation values also recommend uses with assemblies and parts subjected to higher levels of unit vibration during operation.  N’s electrical/physical properties are not noticeably impacted by cycling from -270º C to room temperature, adding to its versatility.  
  •  Parylene F has fluorine atoms on its aromatic ring.  Possessing aliphatic -CH2- chemistry, F’s superior thermal stability is attributed to this aliphatic C-F bond, compared to Type C’s C-C bond.   Better thermal stability, and reduced electrical charge/dielectric constant expand its use for ILD (inner layer dielectric) applications, such as those for ULSI (ultra large-scale integration), where a single chip can incorporate a million or more circuit elements.   F is a good choice for many microelectromechanical systems (MEMS)/nanotech (NT) solutions. 
  • Originating from the same monomer as Type C, Parylene D’s chemical composition contains two atoms of chlorine in place of two hydrogen atoms.  Like Type C, D conformal films can perform at 134° C (273° F), dependably securing assembly performance in oxygen-dominated environs for 10 years, at a constant 100° C.  Parylene F resists higher operating temperatures and UV light better than C or N.  
  • Parylene AF-4’s melting point is greater than 500° C.  It survives at higher temperatures/UV-exposure better than other parylenes for long durations because it possesses CF2 units, situated between its polymer-chain rings.  
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Tags: parylene, parylene properties, parylene temperature, parylene C, parylene f, parylene d, parylene af-4

Effects of Adhesion Promotion on Sensors

Posted by Sean Horn on Fri, Oct 26, 2018 @ 07:30 AM

Sensors measure specific aspects of data-driven technology.  Included are such performance properties as acceleration, fluidity, humidity/temperature, position, pressure or vibration.  Sensors collect data  and respond with feedback for a multitude of electronic devices utilizing printed circuit boards (PCBs) and related sensitive electronics.  They have been successfully adapted for use across a wide range of applications, including aerospace/military, appliance, automotive, communications, consumer, industrial, medical and transportation uses.  

PCBs and the larger devices they power often need to function in harsh operating environments.  Conformal coatings -- liquid acrylic, epoxy, silicone and urethane resins, and chemical vapor-deposited (CVD) parylene – provide PCBs and similar electronics excellent barrier, dielectric and insulative protection through most performance conditions, sustaining their expected utility.  Substrate adhesion is necessary to conformal film reliability; coatings do not work if they delaminate or otherwise disengage from the components they are applied to protect. 

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Tags: parylene inpsection, parylene adhesion, sensors

Crevice Penetration of Parylene

Posted by Sean Horn on Fri, Oct 19, 2018 @ 07:30 AM

Parylene (XY) polymers provide robust, dielectric, micron-thin conformal coatings for a considerable range of electronic devices, most prominently printed circuit boards (PCBs).  XY’s unique chemical vapor deposition (CVD) application method synthesizes in-process, depositing gaseous parylene deep into a substrate’s surface.  CVD occurs on a molecule-by-molecule basis, conforming to all underlying contours, regardless of shape or position, to the nanometer, if necessary.  Pre-synthesized liquid coatings lack many of parylene’s performance properties, having far less ability to successfully and conformally penetrate crevices in the substrate

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Tags: conformal coating properties, parylene properties, parylene coating process

Cleaning Methods for Conformal Coating

Posted by Sean Horn on Fri, Oct 12, 2018 @ 07:30 AM

Cleaning the substrate is an essential element of preparation for conformal coating.  The reasons are easy to understand:

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Tags: cleanliness testing, cleaning, conformal coating process

Parylene Coating Measurement Methods

Posted by Sean Horn on Fri, Oct 05, 2018 @ 07:30 AM

 Used as moisture and dielectric barriers, polymer parylene (p-xylylene/XY) coatings are conformal and pinhole free.  Applied by a unique chemical vapor deposition (CVD) method, parylene penetrates beneath substrate facades, simultaneously attaching above surfaces at the molecular level.  CVD generated films cover crevices, exposed internal regions, points and sharp edges uniformly, without gaps or breaches.  Compared to liquid coating materials – acrylic, epoxy, silicone and urethane -- XY film layers are micron-thin, enhancing their utility for microelectricalmechanical systems (MEMS) and nano technology (NT). 

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Tags: parylene thickness, parylene coating process, conformal coating inspection

Parylene for Medical Sensors

Posted by Sean Horn on Fri, Sep 28, 2018 @ 07:30 AM

          Many medical devices rely on sensors to detect and measures conditions affecting patient health.  Generally, physical properties within the body – heartbeat, blood pressure, breath rate, temperature, -- are recorded and transmitted to medical personnel/technology, allowing continuous physiological monitoring of health-specific disorders, to improve the quality of diagnosis and treatment. 

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Tags: medical device coating, medical parylene uses, medical parylene

What do I need for a Parylene Coating Quote?

Posted by Sean Horn on Fri, Sep 21, 2018 @ 07:30 AM

          Parylene’s (XY) reputation as the most versatile and reliable of major conformal coating materials is well-earned.  However, unlike liquid coatings –resins of acrylic, epoxy, silicone and urethane – parylene cannot be applied via relatively economical brush, dip or spray methods.  XY can be the most expensive of the major conformal coatings to use, a factor influenced both by:

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Tags: parylene coating service, conformal coating service, parylene process

Can Parylene be used as a Standalone Enclosure?

Posted by Sean Horn on Fri, Sep 14, 2018 @ 07:30 AM

Parylene (XY) polymer conformal films are recognized for their exceptional range of desirable functional properties for coating printed circuit boards (PCBs) and similar electronics.  Beneficial properties include biocompatibility, chemical/solvent resistance, dielectric/insulative reliability, and ultra-thin pinhole-free film thicknesses between 1-50 μm.  They also generate complete surface conformability, regardless of substrate configuration, exceeding the coating capabilities of liquid conformal materials, such as acrylic, epoxy, silicone and urethane.   

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Tags: parylene process, parylene properties

Elongation Properties of Parylene

Posted by Sean Horn on Fri, Sep 07, 2018 @ 03:04 PM

For conformal coatings, elongation is a measure of material ductility -- a specific coating's ability to undergo significant plastic deformation before rupture.  A coating’s yield elongation is the maximum stress the material will sustain before fracture.  Thus, computed parylene (XY) elongation measurements represent the total quantity of strain the conformal film can withstand before failure.  While elongation is equal to a material’s operating failure strain, it has no exclusive units of measurements.  Typically,

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Tags: parylene properties, parylene process, parylene coating process