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Browse our blog to learn more about thin film and conformal coating processes, material, and application. Find out more about HZO and how our solutions can help your market.

PECVD vs CVD – Chemical Vapor Deposition Overview

Thin-film deposition is the dynamic process used for depositing thin-film coatings onto a substrate, part, or assembly. Deposition methods, in general, can be grouped into three..

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How to Choose a Nanocoating Material

As engineers, it is our job to bring products to life and ensure they operate as expected until the end of the product life cycle. Therefore, a large part of our job is to prevent..

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Overview of the Plasma Nanocoating Process

Nanocoatings, thin films measured at the nanolevel, serve numerous purposes. But for many product design engineers, the ability to safeguard electronics with protection..

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How Small is a Nanometer? Nanometers Explained

We live in a growing world. Every day, cars are getting bigger, buildings are getting taller, phones are getting larger, and Americans are getting wider (I can say that; I’m an..

Read More

PECVD vs CVD – Chemical Vapor Deposition Overview

May 7, 2021 / by Ryan Moore posted in Coating Process, PECVD Coatings

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Thin-film deposition is the dynamic process used for depositing thin-film coatings onto a substrate, part, or assembly. Deposition methods, in general, can be grouped into three categories – liquid coating deposition techniques, physical vapor deposition, and chemical vapor deposition. This article will focus on chemical vapor deposition and one of its variants, plasma-enhanced chemical vapor deposition (PECVD).

 

Download our white paper on choosing the correct coating methodology for your next project:

 
 

Chemical Vapor Deposition Methods

Chemical vapor deposition (CVD) methods (including but not limited to CVD, PECVD, and atomic layer deposition, ALD) are done under vacuum, well below atmospheric pressure, as the process deposits layers of material molecule-by-molecule or atom-by-atom. With these techniques, thin-film layers can be deposited in the range of nanometers to sub-20-micron, compared to traditional deposition, which yields coatings at 50-500 microns.

Read "How Small is a Nanometer?" 

No matter the method, vapor deposition produces coatings that alter the substrates’ electrical, mechanical, optical, thermal, and corrosion-resistance properties. The resulting dry coatings are durable and have reached optimal properties without curing at the end of the production cycle.

Below is an overview of the chemical vapor deposition process.

 

Overview of the Chemical Vapor Deposition Process

The CVD process deposits materials, including Parylene, in a vacuum chamber by vapor deposition polymerization. The item to be coated is exposed to one or more precursors, which decompose or react on the surface. In the instance of Parylene, a solid dimer is vaporized to gas. Before entering the deposition chamber, the gas travels through a pyrolysis chamber that cracks the dimer into two di-radical monomers. The monomers adsorb onto the substrate as a polymer.

 

an Overview of the Chemical Vapor Deposition Process

 

Chemical vapor deposition is used to augment substrate surfaces in ways that traditional modification techniques cannot. Polymerization by CVD allows for thin coatings with properties such as lubricity, weather resistance, and hydrophobicity.

Chemical vapor deposition is a repeatable process that produces consistent coverage and reliable results. Applications include:

Many hybrid application techniques arise from CVD, evolving to modify the properties of fabricated thin films. Among these variants, PECVD is a method that can extend the applicability of the technique for reactive and inorganic materials, inert materials, and various precursors. This technique is discussed below.

Overview of the Plasma Enhanced Chemical Vapor Deposition Process

Plasma-enhanced chemical vapor deposition is a variant of CVD; however, it uses plasma energy instead of only thermal energy to deposit thin films. The plasma is typically created by radio frequency, direct current, or microwave discharge that energizes reactant gases, such as silane or oxygen, to form a plasma. The deposition equipment uses a mixture of ions, free electrons, radicals, excited atoms, and molecules to deposit thin-film coatings to the substrate. Parts in the chamber are bombarded with energetic ions (plasma) that form a thin-film layer on the surface made from metals, oxides, nitrides, and/or polymers (fluorocarbons, hydrocarbons, silicones).

 

PECVD Process Diagram

 

 

PECVD-deposited films have excellent physical properties because they are uniform, highly cross-linked, and generally resistant to chemical and thermal changes. Plasma-applied polymers are extensively used in optical coating and dielectric films due to their lower cost and higher efficiency properties. Offering excellent control of material properties (stress, refractive index, hardness), PECVD also produces films used in the semiconductor industry for device encapsulation, surface passivation, and isolation of conductive layers.

Different film compositions can easily be adjusted to produce organic thin films on large substrates (glass and silicon) with varying chemical, thermal, optical, electrical, and mechanical properties. PECVD has also recently been used for many biological applications, including medical device protection, and is also used to avoid corrosion in optical and dielectric devices.

This nanocoating process can use various materials as coatings, including metals, oxides, or silicon, which may offer more flexibility than CVD. Applications include:

  • Fabrication of electronic devices to isolate multiple conductive layers, capacitors, and for surface passivation
  • Solar cells, semiconductor devices, and optically active device applications due to optical, mechanical, and electrical properties
  • Processing of printable electronic devices due to high process efficiency, large-scale patternability, lower cost, and environmentally friendly nature
  • SiN (silicon nitride) PECVD films are used for semiconductor applications due to higher capacitance density, breakdown voltage, and particle performance.
  • SiC (silicon carbide) PECVD films have demonstrated promise in developing high-temperature withstanding MEMs devices.

Read more about nanocoating material

CVD Benefits

When used with Parylene, CVD brings many benefits to the table, including:

  • Ultimate thin-film barrier material for liquid water, water vapor, and harsh chemical corrosion (acid, alkali, organic reagents)
  • Excellent dielectric strength to provide dielectric and insulative protection across an extensive range of frequencies
  • Highly conformal and adherent to many surfaces (metals, glasses, plastics, silicon, ceramics)
  • Entirely non-toxic (safe for all human contact, including implantable devices) and green (non-hazardous processing)

Download our introductory guide to protective coatings

 

CVD Drawbacks

In comparison with PECVD, CVD can have the following drawbacks:

  • Higher cost: long deposition time (10-20 hrs) need for masking/demasking (80%-line cost), and high precursor (dimer) cost
  • Relatively thick film (typically 10µm minimum thickness needed for high integrity pinhole-free conformal coating)
  • Limited operating range/life due to the aging effects of heat (>50°C), oxygen (air), and UV (sunlight) exposure
  • Low wear resistance and mechanical durability limits use on exterior surfaces (cases, enclosures)

PECVD Benefits

PECVD offers the following benefits:

  • Ability to create “nano”-thin barrier films (50nm+) with low stress (room temperature process)
  • Lower cost: due to fast deposition times (accelerated by RF field) and relatively low cost/low use precursor materials
  • No need for masking/demasking to prevent coating on non-target part areas: the coating may be shielded using the part-holders
  • High tailorability: recipe changes facilitate diverse coating properties, including hydrophobic surfaces, UV protection, oxygen resistance, reworkability, and more

PECVD Drawbacks

In comparison with CVD, PECVD can have the following drawbacks:

 
  • Barrier performance is weaker than Parylene and highly dependent on the film thickness, layer count, and plasma type.
  • Limited wear resistance: materials are typically soft (enables rework but exacerbates handling issues).
  • Some coatings may be halogenated, raising health and environmental concerns.

Although this article has provided an overview of CVD and PECVD, it is only a high-level discussion. Chemical vapor deposition processes are a good choice for thin-film deposition, but selecting the proper method takes significant experience and technical acumen from a domain expert. HZO offers highly customizable protection solutions with both CVD and PECVD processes. If you have difficulty deciding which thin-film deposition method to use, contact us today to consult with our engineers.

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How to Choose a Nanocoating Material

April 28, 2021 / by Mallory McGuinness-Hickey posted in Coating Properties, PECVD Coatings

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As engineers, it is our job to bring products to life and ensure they operate as expected until the end of the product life cycle. Therefore, a large part of our job is to prevent premature failure by providing electronic products with appropriate protection from environmental threats that can cause an immediate or unplanned shutdown. To do this, we must evaluate protective solutions and sometimes think outside the box. We may need to rethink protection in a landscape punctuated by miniaturization, ruggedization, and sustainability concerns. Nanocoating technology can often address these needs better than current methods like gasketing, protecting products from liquid damage and its subsequent harm to business reputation.

 

Hydrophobic Nanocoatings to Improve Performance

Protective nanocoatings are thin films of coating material measured in thicknesses of nanometers applied directly to the surface of PCBAs and other components or materials. With nanocoatings, product design teams can meet many objectives, including material hydrophobicity (water-repellent) due to the low surface energy of the coating. This may be important for a wide range of applications, like increasing the water resistance of electronics, helping your down sleeping bag stay dry, or allowing water to bead off car windshields more easily. Nanocoatings' other protective capabilities include corrosion protection, hardness, or, sometimes, oleophobic properties (oil repellent).

To effectively apply hydrophobic coatings of this caliber, vacuum deposition is required to ensure the quality and consistency of the application. Plasma-enhanced chemical vapor deposition (PECVD) is a popular nanocoating process because it is flexible, controllable, and appropriate for various applications. PECVD utilizes plasma, a high-energy, gaseous state that enables material to deposit onto substrates. The process parameters vary tremendously, including power, plasma type, temperature, deposition time, pressure, gas flows, and gas composition. Adjustments to these parameters make it possible to produce highly-performing thin films tailored to your protection requirements. Due to the versatility of the PECVD process, a wide range of materials can be deposited to help engineer a specific coating solution.

The material you ultimately use for deposition is closely related to coating performance, so it is essential to select carefully. The criticality of material choice begs the question: how do you choose the best nanocoating material for your project?

 

Download our HZO Nanocoating Datasheet

 

 

Choosing the Right Nanocoating Material

 

There are halogenated materials (fluorocarbons and chlorocarbons) and halogen-free (silicones, hydrocarbons, metal oxides, and metal nitrides). Ultimately, performance requirements and sustainability concerns will determine which is preferable.

Halogenated Materials
Halogenated material processes produce coatings with high hydrophobicity or strong etching capabilities. Halogen-free material processes, such as silicones and metal oxides, deposit coatings that serve as strong water barriers, offering strong performance.

Halogen-Free Materials
Sometimes non-halogenated materials are preferable for environmental reasons. If you are considering halogen-free materials, the choice does not end there. You’ll have to consider other requirements. For example, metal oxides may provide more substantial protection, but a hydrocarbon coating may provide acceptable performance and is generally easier to handle than other materials.

 

Understanding the Performance Requirements

 

While understanding if you prefer halogenated or halogen-free materials will be a critical part of your decision, you must thoroughly understand your product’s performance requirements to choose which material to use. Hydrophobic, hydrophilic, and corrosion resistance properties will determine whether a fluorocarbon, silicone, metal oxide or another material is preferred.

 
hydrophobic nanocoating

 

After You Have Chosen a Nanocoating Material

After determining what material type to use, the selected material will determine the precursor (materials that chemically react and/or decompose on the substrate’s surface) and plasma parameters to use. Different gas or liquid precursors result in different coatings. For example, methane may be used as a simple hydrocarbon coating, carbon tetrafluoride for a fluorocarbon, or hexamethyl dioxolane for silicone.

Even after determining the precursor, the flow rates of that liquid or gas and other parameters can dramatically affect the final coating properties. For example, adding oxygen, nitrogen, or argon can completely change the results. Argon is inert in the overall reaction, but it may change the reaction mechanism, which is the sequence of steps that make up the overall reaction. The mechanism affects what film is deposited. Adding oxygen may create oxides, and nitrogen may form nitrides, which add to the film’s hydrophilic properties. Meanwhile, different flows of the same gases may result in different coating properties. Gas flows may range from a few sccm (standard cubic centimeters per minute) to 10,000 sccm or more. This flow rate difference may change the reaction mechanism, altering what is deposited.

 

Seeking Technical Expertise

As you can see, with PECVD, there are many options where significant experience and development will be required to understand which materials are best. If you are interested in PECVD coating technology and want help getting started, please reach out today for a consultation. 

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Overview of the Plasma Nanocoating Process

March 26, 2021 / by Mallory McGuinness-Hickey posted in Coating Process, PECVD Coatings

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Nanocoatings, thin films measured at the nanolevel, serve numerous purposes. But for many product design engineers, the ability to safeguard electronics with protection capabilities such as hydrophobicity, corrosion-resistance, and dielectric and thermal properties, is top of the list. Protective nanocoatings empower organizations to mitigate risk associated with downtime, reduce repairs and warranty claims, and cultivate market confidence with remarkably reliable electronic products.

Download our white paper on thin-film coating depositions, including PECVD and a summary of PECVD vs CVD

 

 

Plasma Surface Technology Benefits

Plasma application processes can produce nanocoatings with many beneficial substrate surface characteristics, including:

  • Hydrophobicity
  • Oleophobicity
  • Humidity/temperature protection
  • Excellent flammability protection
  • Low dielectric constant with good high-frequency properties
  • Good dielectric strength and high bulk and surface resistance
  • Splash protection
  • High barrier protection against corrosive chemicals and gases while providing low permeability to moisture

These valuable benefits have piqued interest in plasma-based nanocoatings and the processes used for their deposition.

Read "How Small is a Nanometer?"

Plasma Coating Processes

While several methodologies exist to apply nanocoatings to substrates, including plasma spray deposition, plasma-enhanced chemical vapor deposition (PECVD) is popular due to enhanced process control and beneficial physical film properties.

 

a chart explaining the nanocoating process

PECVD Process

 

The PECVD Plasma Application Process

PECVD harnesses plasma energy to deposit nanocoatings through several power sources, including microwave discharge, radiofrequency, and direct current. Using PECVD equipment, gases are energized to form a plasma and a mixture of ions, radicals, excited atoms, free electrons, and molecules to deposit the nanocoatings.

Possible materials to form the coatings include metals, polymers (silicones, hydrocarbons, fluorocarbons), oxides, and nitrides, representing many possibilities. The resulting films are highly cross-linked, dense, pinhole-free, and uniform; these attributes lend to good physical properties.
The process offers precision control over these film properties, yielding various chemical, thermal, mechanical, electrical, and optical benefits.

 

HZO PRO800-PL Proprietary Nanocoating Coating Equipment

HZO PRO800-PL Nanocoating Equipment

 

PECVD Parameters to Consider for Optimal Performance

Internal and external plasma parameters may be modified to affect the resulting film. Internal plasma parameters include the precursors used, the distribution of various species in the plasma and the species’ energy, and the homogeneity of discharge. External parameters include temperature, applied power, total pressure, gas flow rates, pumping speed, and reactor geometry.

PECVD Benefits

The deposition process allows for a wide range of material usage, including unconventional precursors that can deposit on surfaces with complex geometries, typically at lower temperatures than other vacuum deposition processes, such as thermal chemical vapor deposition. It is possible to tightly and efficiently control these precursors while generating few by-products, allowing for precise film composition and uniformity control. As a result, PECVD nanocoating chemistry is unique and often unobtainable with standard liquid coating deposition methods.

 

PECVD Applications

PECVD coatings are used in applications that require lower cost and high efficiency, including optical coatings, corrosion resistance, and dielectric films.

Applications include:

  • Mobile phones
  • Earbuds
  • Smart speakers
  • Wearables
  • Outdoor cameras
  • Hearing aids
  • Catheters
  • Smart patch
  • Connected health devices
  • Automotive in-cabin sensors and electronics
  • Automotive cabin filters
  • Automotive cameras
  • Doorbell cameras
  • POS scanners
  • Air quality sensors
  • Smart home applications
  • LEDs
  • Drones
  • HVAC sensors
  • Industrial equipment controller

PECVD Coatings with HZO

At HZO, our in-house designed deposition equipment is optimized for faster deposition rates with scalable reactors for High-Volume Manufacturing (HVM). The fixtures used during the deposition process (directional plasma only) provide an alternative to masking, a process used to ensure coating does not cover parts such as connectors. This alternative can save time and money, as masking and demasking can be labor-intensive.

  • Plasma-based technology leverages a variety of chemistries that can quickly be adapted to specific requirements.
  • Coatings can be single or multi-layer, with one or more chemistries applied. This hybrid approach allows the delivery of target properties.
  • Materials include halogen-free alternatives.
  • Typical thickness varies from 300 nm to 3 µm.
  • Masking requirements can generally be addressed in the chamber as part of the deposition process using a shadow mask to isolate areas to be kept free of coating.
  • Minimal footprint required to perform coating operation.
  • Features include liquid protection, anti-corrosion, etc.
  • Solutions are scalable for high-volume manufacturing at competitive pricing.

Download the HZO Sentinel Series™ Datasheet

 

For more information on our plasma-based nanocoatings, please contact the HZO team with any questions or concerns. Our engineers would love to give you a free consultation to determine if the plasma nanocoating process is ideal for your application.

 
 
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How Small is a Nanometer? Nanometers Explained

November 14, 2014 / by Ryan Moore posted in Coating Properties, PECVD Coatings

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We live in a growing world. Every day, cars are getting bigger, buildings are getting taller, phones are getting larger, and Americans are getting wider (I can say that; I’m an American). But here at HZO, we are getting smaller. In fact, we are obsessed with getting smaller. Every day our engineers, chemists, and recently added physicist work tirelessly to make HZO’s already minuscule technology smaller and even less invasive.

The prefix “nano” is used in many different industries and in many different contexts, but no matter the situation, it is used to describe something that is really, really, incomprehensibly tiny. In fact, it’s used to describe and measure things on the molecular level.

But how small is small? Let’s put it into perspective.

  • The Empire State Building is more than 443,000,000,000 nanometers tall.
  • Shaquille O’Neal is 2,160,000,000 nanometers tall.
  • A single hair on your head is 100,000 nanometers wide.
  • A common germ is about 1,000 nanometers wide – I don’t know about you, but the fact that we can measure a germ makes me want to wash my hands more often.

 

So what’s the big deal? Why does this matter? At just 5,000 nanometers, our coating is 20X thinner than a single strand of hair (and if you’re counting, that’s 43,200X thinner than Shaq). Unlike other materials, HZO’s nanotechnology bonds to practically any surface and creates a tight, conformal layer that keeps corrosives and contaminants at bay. Our nanocoating process offers a robust protection solution against liquid submersion for electronic components and devices. Since our micro-thin material is applied directly to the electrical components, there is no change in the weight, look or feel of the device after the treatment has been applied.

So, long story short, and a few useless facts later, HZO protects your devices in ways that no other technology can by applying a thin film that is durable and consistent, protecting electronics from corrosion and failure that occurs as a result of exposure to any kind of liquid. It protects at the microscopic level, and it doesn’t just keep water and other liquids away from the all-important electronic components, but it literally changes how these liquids and corrosives react to the protected surface. Contact us today if you have a device or product you want to protect.

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