Plasma Desmearing Explained Simply

Plasma desmearing (using low-pressure plasma) refers to the precise removal of drilling smear from printed circuit boards (PCBs). This is a critical process in PCB manufacturing for removing residues (smear) from fine through-holes (vias) in modern multilayer designs. The removal of drilling slurry ensures reliable connections prior to metallization.

Why desmearing is necessary

The mechanical drilling of vias in multilayer printed circuit boards generates heat that melts the resin (e.g., FR4). As it cools, this resin—often mixed with drill dust—forms an insulating layer on the inner copper layers within the drill hole. This layer is referred to as “smear” or “drilling residue.”

Smear and associated problems

What is smear?
Smear refers to resin residues that result from the mechanical drilling of holes (vias) during PCB manufacturing. The mechanical drilling generates heat, which causes the resin (e.g., FR4) to melt. As it cools, an insulating layer forms on the inner copper layers within the drill hole, often mixed with drill dust. This layer is referred to as “smear” or “drilling residue.”

Common Problems
Untreated multilayer printed circuit boards often suffer from poor electrical connections because smear acts as an insulator. This prevents direct or reliable contact between the inner layer and the copper sleeve that is later electroplated. This leads, among other things, to:
– Defects & failures: Insufficient bonding can lead to increased resistance, intermittent contacts, or even open circuits.
– Reduced reliability: Smear is particularly unacceptable in high-reliability applications (medical technology, automotive, aerospace).

Desmearing methods and their limitations

Traditionally, desmearing is performed using wet chemical processes, typically with concentrated chemicals such as potassium permanganate in a strongly alkaline solution. Disadvantages of wet chemical processes:

• Use of aggressive chemicals.
• High water consumption and wastewater pollution.
• Difficult process control for very fine structures and high aspect ratios.
• Potential material incompatibilities with modern PCB materials.
• Less uniform results in deep, narrow drill holes.

Low-Pressure Plasma: The Top Solution

Low-pressure plasma technology offers a superior alternative to conventional desmearing using wet chemistry. In this process, printed circuit boards are placed in a vacuum chamber.

A process gas (or gas mixture) is introduced at low pressure (typically 0.1–1 mbar) and ionized by an energy source, creating low-pressure plasma or vacuum plasma.

Plasma reaches micro, blind, and buried vias, among other areas, where wet chemistry reaches its limits. This is indispensable, for example, for HDI (High-Density Interconnect) printed circuit boards.

The plasma desmear process ensures ultra-fine cleaning of the drill holes, effectively removing smear or resin residues from the surfaces. This ensures clean via walls and thus improves electrical conductivity.

Unlike chemical methods, our low-pressure plasma does not etch or weaken the copper and even improves copper adhesion to surfaces. Additional benefits include:

• Uniform and controlled cleaning of PCBs ✓
• Clean through-holes regardless of complexity ✓
• Works for PCB materials such as FR4, polyimide, or PTFE ✓
• Ideal for HF, microwave, and high-frequency PCBs ✓
• No use of toxic chemicals or disposal ✓
• Increased workplace safety and environmental protection ✓

In short: Desmearing with low-pressure plasma is environmentally friendly, reliable, and cost-effective.

Plasma sterilization explained simply – Definition

Plasma sterilization is an innovative, fast, and highly effective low-temperature process (45 °C to 60 °C) for the residue-free elimination of germs and pathogenic microorganisms. It is typically used in pharmaceutical and medical fields and frequently in the packaging industry.

Advantages

The low-temperature process offers significant advantages—such as efficiency, gentleness on materials, sustainability, and workplace safety—over conventional sterilization methods such as steam (+100 °C) or ethylene oxide gas (toxic and leaves residues).

Due in particular to its thermolabile properties, which are beneficial for heat-sensitive instruments, dry plasma sterilization is suitable for materials sensitive to heat and moisture. These include, among others, surgical materials, plastics, dental instruments, cables, and aerospace materials.

Disadvantages

Plasma sterilization has fewer disadvantages and more limitations. For example, the items being treated must be completely dry and, when using low-pressure plasma, must also be vacuum-tight and plasma-resistant. Because the plasma treatment takes place in a vacuum chamber, even objects with complex geometries or cavities can be sterilized effectively—something that is not always possible without a reaction vessel.

plasma technology’s approach: Our plasma systems therefore use only low-pressure plasma for sterilization. This ensures efficient processing times, and thanks to the high durability of our products, our solutions are both efficient and cost-effective.

Applications for Materials and Products

Suitable products and materials for plasma sterilization or disinfection. Which products or materials can be disinfected or sterilized in low-pressure plasma?

Materials

In addition to various metals, polymers (plastics)—such as thermoplastics, thermosets, elastomers, TPU, and, in particular, silicones—can also be cleaned, disinfected, and sterilized using plasma. Glass, ceramics, and various textiles and membranes are also suitable for plasma sterilization and plasma disinfection.

In general, materials must be plasma- or vacuum-resistant in order to undergo plasma treatment. Materials that cause significant disruption to the vacuum or plasma due to heavy outgassing are therefore not suitable for treatment in low-pressure plasma.

Products

Typical products suitable for disinfection or sterilization in low-pressure plasma include those from the pharmaceutical, medical, and dental sectors, as well as the packaging industry. For low-pressure plasma sterilization, the products must be able to be placed inside the plasma chambers.

Fixed components, such as hospital interiors, cannot be treated with low-pressure plasma. Additionally, the plasma cannot reach products that are already packaged. In this case, the plasma sterilizes only the packaging, not the product itself.

Examples of products that can be successfully disinfected and sterilized in low-pressure plasma:

• Respiratory masks
• Safety goggles
• Surgical instruments
• Dental instruments
• Catheters and prostheses
• Endoscopes (thermolabile)
• PE, PP, and blister packaging

Even FFP3 respirators and other protective equipment for hospital staff, which are normally intended for single use, can be reprocessed for further use through plasma disinfection.

Process and Mechanism

Gas plasma sterilization is a gentle, dry, low-pressure process that oxidizes and completely destroys the cellular components of viable microorganisms. Since it is typically performed at temperatures between 37 °C and 60 °C, it is ideally suited for heat-sensitive materials.

Plasma Sterilization Process

Plasma has been proven to damage or inactivate all components of pathogens, such as bacteria, viruses, virions, prions, and fungi and their spores. This destroys, among other things, their cell walls, viral or spore coats, cell membranes, and the pathogens’ DNA genetic material. Furthermore, plasma removes contaminants and toxins from surfaces.

In a low-pressure process, the items to be sterilized (cleaned and dried) are placed in a sterilization chamber. When using low-pressure plasma, the chamber is evacuated to create a vacuum, and a process gas is introduced.

Due to the high penetrability of low-pressure plasma, even the smallest cavities and crevices are reached during plasma disinfection or sterilization. Depending on the process gas used and the selected treatment intensity and duration in the plasma atmosphere, products are both disinfected and sterilized.

How Plasma Sterilization Works

The scientifically proven sterilizing effect of plasma is the result of several factors.
The factors and how they work in detail:

High reactivity of the particles contained in the plasma
– The various reactive species contained in the plasma damage the organic molecules of living organisms, such as bacteria.
– Bacteria are killed by the oxides present in the plasma.

UV radiation generated in low-pressure plasma
– Ultraviolet radiation is a powerful disinfectant and damages the genetic material of pathogens, i.e., their DNA molecules.
– UV radiation affects living cells, such as bacteria, as well as viruses, which lack their own metabolism.
– Viruses are inactivated by the UV radiation present in the plasma.
– Bacteria are killed by the UV radiation present in the plasma.

High kinetic energy of ions and electrons
– The plasma particles strike the surfaces of the products at high speed, mechanically dislodging existing contaminants and pathogens (sputtering effects).
– Regardless of the nature of the particles—whether living or not—they can be mechanically dislodged, transferred into the gas phase, and removed from the treatment chamber via constant gas transport.
– The charged particles destroy bonds in the cell membranes and thus also penetrate the viral envelopes of enveloped viruses (for information: The SARS-CoV-2 virus is an enveloped virus).

The fine vacuum present in the low-pressure plasma
– The fine vacuum and the temperature increase upon contact with the high-energy plasma species cause the organisms of the pathogens to dry out.

Plasma Disinfection

Plasma disinfection reduces the number of disease-causing microorganisms so that an object no longer poses a risk of infection. These are methods for the targeted, but not complete, killing and inactivation of disease-causing (pathogenic) microorganisms. Disinfected objects are therefore not 100% germ-free, but rather have a reduced or low microbial load. Effective disinfection achieves a KRINKO guideline of approximately 84 to 99.9%. Depending on the process gas used and the selected treatment intensity and duration in the plasma atmosphere, products are both disinfected and sterilized.

Difference from Plasma Cleaning

Plasma cleaning generally refers to the removal of unwanted contaminants and microorganisms without killing or inactivating the latter. In medical settings, cleaning can be performed, for example, using cleaning agents, wipes, or vacuum cleaners.

In the context of plasma, the mechanical removal of microorganisms through sputtering effects corresponds to simple cleaning. Simple cleaning achieves a germ reduction of approximately 50–80%. Plasma disinfection therefore achieves a significantly higher germ reduction than plasma cleaning.

Difference from Plasma Sterilization

The key difference between plasma disinfection and plasma sterilization lies in the (percentage) reduction in the microbial count, which is significantly reduced by disinfection (84 to 99.9%) and completely eliminated without residue by sterilization (100%). Sterile products are therefore free of viable microorganisms, such as bacteria, fungi, or spores. Prions, viruses, and virions must also be inactivated.

Plasma disinfection can be applied to living tissue, e.g., for wound treatment with cold plasma (below 40 °C), and performed on-site.
Plasma sterilization is typically performed in an optimized low-pressure plasma system with appropriate processing times and process gases.

Suitable Plasma Systems and Process Gases

The selection of the appropriate plasma system and process gas depends primarily on the product to be treated. Product quantities, the scheduled timing of disinfection or sterilization, and the desired outcome must also be taken into account.

Suitable plasma systems for sterilization with low-pressure plasma:
If a sterilization process is to be integrated into production, large-volume production systems are the ideal choice. Production systems are adapted to the specific requirements of the products to be sterilized and tailored to existing manufacturing processes. The plasma systems can also be equipped with a pass-through function.

Suitable low-pressure plasma systems for plasma disinfection:
For more mobile on-site use, such as disinfection after the first use of smaller products, small laboratory systems are certainly better suited.

Suitable process gases include various noble gases as well as hydrogen, nitrogen, and oxygen. Mixtures of different gases are also possible. The selection of the process gas depends on the product to be sterilized or disinfected. However, the desired effect of the plasma process is also a factor in the selection.

Plasma Cleaning Definition – What Is It?

Plasma cleaning, also known as ultra-fine cleaning or surface treatment technology, is a dry, physicochemical cleaning process that removes organic contaminants and the finest residues (in the nanometer range) from surfaces.

Plasma cleaning is necessary when surfaces must meet the highest purity requirements and wet chemical processes are insufficient or should be avoided.

As a result, this precise, efficient, and environmentally friendly surface cleaning process is frequently used in industrial manufacturing and medical technology. Plasma cleaning technology is particularly advantageous for industries that perform high-precision processes (e.g., bonding, coating, or assembly).

What does plasma cleaning remove?

Plasma cleaning removes organic contaminants (carbon-containing compounds) as well as inorganic contaminants (non-carbon-containing compounds). Classic examples include dust, salts, fine particles or residues, thin oil films, release agents, or greases. The cleaning process is also frequently used for sterilization or disinfection—that is, the efficient removal of germs, bacteria, or viruses.

What materials is it suitable for?

Plasma cleaning is not suitable for all materials. First of all, they must be able to withstand the vacuum. Materials that contain a high proportion of volatile components, such as water, can be very difficult or even impossible to clean.

Closed-cell foams can be damaged in a vacuum. However, the list of materials that can be cleaned is long and ranges from plastics, glass, and metals to ceramics. Please feel free to contact us for further details.

Plasma Cleaning Process and How It Works

The low-pressure plasma cleaning process is a contactless, high-precision, dry micro-cleaning method for surfaces using plasma (ionized gas). The low-pressure plasma, also known as vacuum plasma, is technically generated in a vacuum chamber. Three main mechanisms are at work in the chamber to ensure optimal performance: chemical cleaning, physical cleaning, and combustion.

Chemical Cleaning

The process gas in the cleaning chamber is excited by a plasma generator operating at a specific frequency. The resulting radicals and ionized particles react with the contamination on the product’s surface. This produces H₂O and CO₂. The environment in the production area remains unaffected by the process—for example, no ozone is produced, as can be the case with atmospheric plasma.

Physical Cleaning

The molecules of the process gas are accelerated by the frequency field. In the process, they strike the product to be cleaned. The high atomic mass causes a kind of micro-sandblasting. The contaminants are removed mechanically.

Combustion – High-Temperature Cleaning

Special conditions are created inside the plasma system’s chamber to generate heat within the product being cleaned. This promotes the outgassing of volatile substances, which polymerize on the surface and can then be removed. A rarely discussed but highly effective process.

Conversely, controlling the conditions during plasma cleaning prevents the product from heating up and discoloring. This applies particularly to conductive materials. Combinations of chemical and physical plasma cleaning can be extremely effective.

Through the use of physical cleaning or ablation, the bonds of contaminants are broken, which are then chemically removed via the gas phase. An interesting side effect is the fact that ionized particles in the plasma chamber dissipate static charges, which facilitates the removal of particles.

Advantages and Disadvantages of Plasma Cleaning

The main advantages of plasma cleaning lie in its precision, environmental friendliness, and efficiency. Commonly cited disadvantages include the high investment and operating costs (of the equipment) or the fact that not all materials can be cleaned using this method.

Advantages

The most important advantages of plasma applications and plasma surface treatments are:

• Highly effective ultra-fine cleaning at the nanometer scale, even for complex geometries.
• No drying process, which means treated materials can be processed immediately.
• Increase or activation of surface energy for optimal adhesion and wettability.
• No environmental impact, e.g., from toxic chemicals or harmful liquid waste.
• Particularly advantageous for the semiconductor/electronics industry, medical technology, and research (among many others).

Disadvantages

When innovative low-pressure plasma systems, such as those from plasma technology, are used properly, there are few disadvantages compared to conventional cleaning methods. Nevertheless, we will address the common concerns that often arise.

• High costs for purchase and subsequent maintenance
  –> To address this, we offer high-quality, durable low-pressure plasma systems that we design specifically for your needs. We also offer cost-effective outsourcing of your plasma applications or our advantageous rental systems.
• Material changes, such as deformation or surface roughening
  –> We have cleaned everything from fine powders and even tiny diamonds to large components and rolls of material without observing any adverse effects.
• No deep cleaning, because plasma only acts where it strikes
  –> Our large chambers, with a volume of 8,000 liters, provide ample space, and our modular plasma generators ensure that the power is evenly distributed throughout the system. Low-pressure plasma thus cleans even the smallest cracks and cavities.

For any questions or concerns, we offer expert advice that is both competent and transparent at any time. We’ll tell you exactly what’s possible and will also honestly point out when a plasma application is less suitable.

Comparison to Conventional Wet Chemical Cleaning

Conventional cleaning methods (using wet chemicals) remove dirt and contaminants using liquids such as solvents, acids, or aqueous cleaners. As a result, components and material surfaces must be allowed to dry afterward.

Compared to conventional cleaning methods, plasma cleaning is a dry process for the precise, ultra-fine cleaning of material surfaces using ionized gas (plasma). In this process, molecules on the surface are effectively oxidized, sandblasted, or bonded.

Difference Between Low-Pressure Plasma and Atmospheric Plasma

Low-pressure plasma (ionized gas) is generated in a vacuum chamber, which is why it is also called vacuum plasma. It is ideal for activating, cleaning, coating, and etching surfaces and components—even those with complex 3D geometries.

• The wide range of contaminants that can be removed.
• Simplified control and repeatability due to fewer parameters.
• The cleaning medium is gaseous and the cleaning process is dry.
• No need to monitor wet chemical cleaning and washing liquids.
• There is no need to dispose of environmentally harmful wet chemical liquids.

Atmospheric plasma is generated at normal pressure and without a vacuum chamber, which is why it is also called atmospheric pressure plasma (APP) or APSA (Atmospheric Plasma Soft Ablation). The ionized gas is produced at normal pressure (ambient air) by applying electrical energy.
Compared to ND plasma, complex 3D geometries or deep cleaning treatments are not possible. Other differences include:

• The atmosphere in the chamber remains constant, thereby preventing recontamination.
• The gas flow rate is in the range of a few milliliters per minute and is therefore not a significant cost factor.
• In most cases, ambient air can be used as the process gas. This results in no costs whatsoever.
• Due to the low pressure in the chamber, there is no risk of fire or explosion when reactive gases such as hydrogen or oxygen are used.
• The exhaust gases contain no ozone, and no active exhaust system is required.

Conclusion

Plasma cleaning is a dry, precision cleaning process that does not involve environmentally harmful wet chemicals. This efficient cleaning method is suitable for many components and material surfaces in the semiconductor, electronics, and automotive industries, as well as for the medical technology and textile sectors. A plasma application for components and surfaces is also advantageous when the highest degree of purity or surface activation is required.

Low-pressure plasma, also known as vacuum plasma, in particular, offers the possibility of treating complex 3D geometries (not possible with atmospheric pressure plasma), internal surfaces, or bulk materials, and achieves fine and uniform cleaning results. For cost-effective operation of low-pressure plasma systems, the leading plasma system manufacturer (plasma technology) offers efficient solutions with comprehensive customer service.

PlasmaKlient Research Project

PlasmaKlient was a funded research project (KMU-innovativ by the BMBF, now BMFTR) conducted in collaboration with Furtwangen University and plasma technology GmbH. From 2019 to 2022, research was conducted on a novel plasma technology designed to improve the environmental friendliness of plasma etching processes by eliminating the release of HFC emissions.

Problem Statement and Necessity

Global emissions of perfluorocarbons (also known as PFCs, F-gases) are a major contributor to climate change due to their extremely high global warming potential and long atmospheric lifetime. Their use was promoted over 35 years ago as an alternative to ozone-depleting CFC compounds in air conditioning and refrigeration systems, sprays, foams, and insulation materials, as well as fire extinguishing agents.

At the latest since the 2016 Kigali Climate Conference, where 150 countries agreed to a drastic reduction in consumption, climate-damaging perfluorinated hydrocarbons have also been regulated. For industrialized nations, a phased reduction of 85 percent by 2036 was agreed upon, while developing and emerging economies committed to reduction targets of 80 and 85 percent, respectively, by 2047. On the surface, these targets are primarily linked to the rapidly growing demand for air conditioning units, for which natural alternative refrigerants such as ammonia, CO2, or propane are already available today. However, the requirements apply equally to industrial production processes.

Dry or plasma etching processes

Conventional dry or plasma etching processes used in semiconductor and printed circuit board manufacturing employ and release significant quantities of fluorinated greenhouse gases. The substances used as etching gases include:

• tetrafluoromethane (CF₄),
• hexafluoroethane (C₂F₆),
• perfluoropropane (C₃F₈), or
• perfluorobutadiene (C₄F₆).

These have a global warming potential 7,390 times (CF₄) to 12,200 times (C₂F₆) that of CO₂.

From a technological perspective, plasma etching plays a crucial role in printed circuit board and semiconductor manufacturing, given the increasingly complex circuit structures and growing demands on the quality of contact and bonding surfaces. For example, the process is used for back-etching circuit layers in multilayer PCB assemblies, surface activation and patterning, or cleaning through-holes for via formation.

In semiconductor manufacturing, it is used, for example, for substrate patterning as well as for cleaning CVD coating systems. Alternative, HFC-free process gases that offer adequate etch rates, process stability, and processing results, or cleaning systems that ensure effective and energy-efficient removal of the highly stable fluorinated compounds from the process exhaust air, are not yet available. Consequently, there is a significant risk that the absolutely necessary reductions in HFC emissions for the printed circuit board and semiconductor industries will soon become a very concrete problem—not only in Europe, but worldwide.

Objectives of PlasmaKlient

To significantly improve the environmental sustainability of plasma etching processes and thereby ensure their long-term viability, PlasmaKlient researched a novel process and system concept and demonstrated its implementation using printed circuit board applications as an example. The research objective was to be achieved through a multi-stage, hermetically sealed, closed-loop plasma process in which the following process steps are directly interconnected:

• Process stage 1: Generation of reactive fluorine from a target.
• Process stage 2: Transfer of the fluorine into a stably regulated, highly abrasive process atmosphere in the so-called etching stage.
• Process stage 3: Chemical recombination of the unused fluorine residues and recycling of the products back to the initial target.

Results

Using a reference application from the printed circuit board manufacturing industry, we were able to make plasma etching more environmentally friendly. We demonstrated that efficient, HFC-emission-free etching processes are possible in a low-pressure plasma system without compromising the functionality of the printed circuit boards.

The success of PlasmaKlient laid the foundation for making another plasma technology process environmentally and climate-friendly in the future, thereby contributing to innovation and sustainability

PlasmaWood Research Project

The PlasmaWood research project was funded by the BMBF (Federal Ministry of Education and Research—now BMFTR) as part of the “KMU-innovativ: Resource and Energy Efficiency” funding program. The central focus of the project was the sustainable treatment of wooden facades using low-pressure plasma to make them more weather-resistant and durable.

Project Management by Jörg Eisenlohr

Under the leadership of Jörg Eisenlohr (Managing Director of plasma technology GmbH), the research project was carried out from October 1, 2021, to March 31, 2024. Approximately €700,000 was allocated to the government funding program “Tapping the Potential of Wood as a Renewable, CO2-Neutral Building Material.”

Low-Pressure Plasma Technology as a Key Factor

Low-pressure plasma technology has led to the development of an environmentally friendly process designed for the sustainable production of weather-resistant wood facades. Wood is one of the oldest building materials in human history, but it is rarely used in modern construction. The main reason is its lack of resistance to external influences, as well as the need for regular and costly surface treatment, which is why plaster facades (87%) are the preferred choice.

PlasmaWood aimed to create new process solutions to make wooden facades higher quality, more weather-resistant, and thus more cost-effective. Plasma coatings, in particular, are known for making material surfaces more dirt- and water-repellent or for preventing rust formation. In this research project, (low-pressure) plasma technology was applied to wood for the first time to investigate whether new potential for sustainable residential and commercial construction could be unlocked.

Testing Procedure Using a Plasma System

In the first step, small standard samples were examined and tested on a laboratory scale. The initial findings were positive. Coatings applied using low-pressure plasma improved both adhesion and stability on the wood samples.

In the next step, a pilot plant was developed and set up to test the positive plasma effects on larger wood samples. Furthermore, research was conducted to determine whether fungal decomposition could be prevented, and additional additives (biocidal additives) for pest control were tested

Successful Wood Preservation Treatment

The test results were positive. Targeted plasma treatments for wood facade elements made them more robust and weather-resistant.

The key benefits include:

• More weather-resistant and durable wood facades
• Lower maintenance costs for outdoor wood surfaces
• Energy savings compared to conventional facade designs
• CO₂-storing wood as a new alternative to common building materials
• More options for future prefabricated wood buildings in the construction industry

The Future with PlasmaWood

Based on successful research findings, plasma-treated wood elements are suitable as sustainable building materials. However, further fine-tuning and optimization are still needed to make PlasmaWood more economically viable and cost-effective.

Plasma treatments are therefore beneficial for many wood elements when it comes to durability and sustainability. To apply them cost-effectively in industry, similar to green hydrogen, further improvements are still needed.
We at plasma technology GmbH continue to conduct research on this topic to establish wood as a climate-friendly, resource-conserving, and economical element in the construction industry.

Plasma Technology Explained Simply

Plasma technology is used for the surface treatment (also known as surface modification) of components and materials. In this industrial process, surfaces are treated in systems using plasma, an ionized gas or the fourth state of matter.

Plasma Surface Modification

In plasma surface modification, material surfaces—such as metals, plastics, textiles, or glass—are cleaned, activated, coated, or etched at the molecular level.

Plasma Cleaning – Ultra-Precision Cleaning

Plasma cleaning, or ultra-precision cleaning, of surfaces is a key application of low-pressure plasma technology. In this process, contaminants are removed from material surfaces through bombardment and chemical reactions with ionized gases, and are then evacuated via a vacuum pump.

In addition, micro-sandblasting can be used to mechanically remove stubborn residues and treat surfaces in a targeted manner. This combined approach ensures residue-free cleaning and optimally prepares the components for subsequent processing or coating processes.

You can also find detailed and comprehensive information in our in-depth article on plasma cleaning.

Plasma Activation

Plasma activation increases the surface energy of materials, removes microscopic contaminants, and modifies surface adhesion to improve the results of industrial bonding, painting, and printing processes.

Furthermore, this form of plasma technology enhances the durability and quality of coatings and paints, as well as the strength of bonded joints.

Through plasma etching or plasma texturing, the reactive species in the plasma remove material from the surface of the substrate. The resulting microstructure creates a larger surface area, which provides more bonding sites for the applied material and, in particular, offers better wettability for liquids.

Plasma Coating and PVD Coating

Plasma coating is a manufacturing process in plasma technology in which materials are coated with an ultra-thin layer (thin-film technology). By introducing monomers, polymers are deposited, imparting new surface properties to the coated workpiece.

The type of monomer selected, as well as the process gases, determine the functionality (hydrophilic, hydrophobic, anti-fog, scratch-resistant, etc.) of the polymerized layer. Additionally, adhesion-promoting functional layers (plasma primers) can be created to serve as a bond between the base material and the subsequent coating. Plasma coating, like activation, is an efficient plasma technology for finishing material surfaces and increases their wear and corrosion resistance.

In PVD coating, atoms are released from the surface of a target (e.g., a metal plate) and deposit onto the surfaces of a component. This process can be used, for example, to metallize surfaces. The layers are very thin (in the nanometer range) and therefore do not alter the component’s volume.

Plasma Etching (Micro-Sandblasting)

Plasma etching is a precise process for removing minute amounts of material at the micro-scale in order to modify extremely fine surface properties or create the finest structures. Plasma etching of polymer surfaces is achieved through extended exposure times.

The removal of material and the resulting roughening of the surface provide a larger surface area for the coating material. Plasma etching of the surface is necessary to improve adhesion, particularly for high-performance plastics such as PTFE, POM, PA, and PEEK. This plasma technology process is a key factor, especially in the semiconductor and microelectronics industries.

Plasma Surface Treatment: A Simple Overview

• Plasma cleaning is a highly precise cleaning process for material surfaces designed to remove organic contaminants, such as oil, grease, or release agents.
• Plasma activation, also known as functionalization, increases the surface energy of materials to improve adhesion and enhance wettability.
• In plasma coating, a functional and ultra-thin layer (usually in the nanometer range) is applied to achieve hydrophobic, hydrophilic, or corrosion-protective effects.
• Plasma etching is a targeted material removal process that enables precise surface structuring (also cleaning, but by subtraction rather than functionalization) at the nanoscale.

Plasma Treatment Systems

A plasma treatment system cleans, activates, coats, or modifies a wide variety of material surfaces, such as metal, plastic, glass, or textiles. The two best-known and most advanced types of plasma systems are low-pressure plasma systems and atmospheric-pressure plasma systems.

Low-Pressure Plasma Systems

In a low-pressure plasma system (vacuum plasma), artificial plasma is generated in a vacuum chamber by applying energy. The workpiece to be treated is placed in this chamber and modified in a targeted manner. The use of low-pressure plasma in the closed chamber also enables efficient plasma treatment of 3D geometries.

During the process, fresh gas is continuously supplied and the spent gas is extracted. The pressure range is typically between 0.1 and 1.0 mbar. After the treatment is complete, the chamber is vented and the treated item is removed.

Atmospheric Pressure Plasma Systems

An atmospheric pressure plasma system (Openair plasma) generates plasma under ambient conditions and does not require a vacuum chamber. Since a vacuum chamber is not necessary, these systems are somewhat more affordable and can be used for inline processes (e.g., production lines).

The disadvantages of these systems include lower precision, a limited effective range, and geometric constraints when performing plasma treatments at atmospheric pressure compared to low-pressure plasma.

Plasma Technology: Areas of Application

(Low-pressure) plasma technology has many areas of application and is therefore used across a variety of industries. The most common areas of application and industrial sectors include, for example, the automotive, semiconductor, plastics, packaging, metal, textile, and medical industries.

Consequently, plasma technology must meet many industrial requirements and be adapted for specific processes and techniques. As a leading manufacturer of plasma systems, we at plasma technology specialize precisely in this area. An overview of our customers and industries that rely on innovative plasma technology follows below:

Automotive Industry

Plasma technology is an essential factor in the automotive industry for the treatment of many components.

• Removal of manufacturing residues through plasma cleaning.
• Removal of silicone residues through plasma cleaning.
• Plasma activation as a pretreatment for bonding or painting.
• Plasma etching of high-performance plastics.
• Plasma coating as an adhesion promoter (plasma primer).

Electrical and Electronics Industry

Plasma technology is extremely important in the electrical and electronics industry when it comes to applying ultra-thin coatings or cleaning components.

• Bond pretreatment via plasma cleaning.
• Borehole cleaning via desmearing.
• Removal of silicone residues via plasma cleaning.
• Soldering pretreatment via plasma cleaning.
• PECVD coating and plasma etching.

Plastics Industry, Packaging Technology, and Elastomer Technology

In the plastics industry, packaging technology, and elastomer technology, plasma technology is a precise, gentle, and environmentally friendly method for optimizing surfaces such as PP, PE, EPDM, or PC.

• Removal of manufacturing residues through plasma cleaning.
• Removal of silicone residues via plasma cleaning.
• Removal or elimination of bacteria or germs via plasma sterilization.
• Plasma activation as a pretreatment for bonding or painting.
• Plasma etching of high-performance plastics.
• Plasma coating as an adhesion promoter (plasma primer).

Medical Technology

In medical technology, cold plasma is essential for sterilization, wound healing, and dermatology, as it effectively kills germs and bacteria. Plasma technology is also important for coating medical devices and much more.

• Removal of manufacturing residues through plasma cleaning.
• Removal of silicone residues through plasma cleaning.
• Removal of oxides through surface reduction with plasma.
• Corrosion-resistant surfaces through plasma coating.
• Plasma coating to improve sliding properties.
• Removal of bacteria or germs through plasma sterilization.
• Activation of plastic surfaces for further processing.

Metal Industry

In the metal industry, plasma technology is an indispensable high-performance process because it involves working at extremely high temperatures. Whether it’s precision plasma cutting, activation, ultra-fine cleaning, coating, or plasma etching, this industry requires versatile plasma processes and techniques.

• Removal of manufacturing residues through plasma cleaning.
• Removal of silicone residues through plasma cleaning.
• Removal of oxides through surface reduction with plasma.
• Plasma coating as corrosion protection.
• Plasma coating to improve sliding properties.
• Plasma coating as an adhesion promoter (plasma primer).

Textile Industry

Plasma technology is an environmentally friendly, gentle, and modern method for finishing textiles. Hydrophobization (water repellency), hydrophilization (wettability and dyeability), and functionalization (cleaning) are important plasma applications for the textile industry.

• Improvement of textile wettability through plasma pretreatment.
• Improvement of sliding properties.
• Plasma coating with hydrophobic properties.
• Plasma coating with hydrophilic properties.

Definition of Plasma – What Is It?

Plasma is (in physics) a high-energy, ionized gas and the fourth state of matter, of which it consists of over 99% (visibly). It forms when a gas is supplied with so much energy, e.g., heat or electrical voltage, that the electrons are separated from the atoms (ionization).

Plasma is therefore an ionized gas in which molecules and atoms have released their electrons and are electrically conductive. Since it reacts to electromagnetic fields, it is often luminous. Plasma effects can be observed in nature, for example as the aurora borealis or lightning, but especially as the sun and stars.

This diagram provides a simplified illustration of the composition of plasma.

Hot Plasma and Cold Plasma

The difference explained simply: Hot plasma is hot—that is, in thermal equilibrium—while cold plasma is cold—that is, not in thermal equilibrium—which is why the difference lies in their temperatures.
In hot plasma, charged ions, free electrons, and some neutral atoms are in an extremely hot state (often millions of °C) and are in thermal equilibrium.
In cold plasma, only the electrons are excited or hot, while ions or atoms are at room temperature (ambient temperature) and are not in thermal equilibrium.

Low-pressure plasma explained simply

Low-pressure plasma is a technically generated plasma that is non-thermal (or cold) and has a pressure significantly lower than Earth’s atmospheric pressure. It is produced by ionizing a gas in an evacuated vacuum chamber using an energy source. For this reason, it is often referred to as vacuum plasma.

Technical production in a low-pressure plasma system
A low-pressure plasma system essentially consists of a vacuum chamber, a vacuum pump, a gas supply system, a medium- or high-frequency generator, and an electrode. It is operated using electricity. In the first step, a workpiece is placed in the vacuum chamber and the vacuum pump extracts the air, creating a vacuum or low pressure.

An electric field is generated using electricity. A gas or process gas (e.g., O₂) is introduced into the electric field at a pressure of approximately 0.1 mbar. The pressure range is between 0.1 and 1.0 mbar. The gas is ionized by the application of energy (usually electricity), and a plasma is formed.
At low pressures of < 100 Pa (1 mbar), a cold plasma is generated in a vacuum chamber. By applying electromagnetic fields, the gases or gas mixtures contained in the chamber are ionized and thus converted into the highly reactive plasma state.

Atmospheric Pressure Plasma Explained Simply

Atmospheric pressure plasma (APP) is generated using compressed air or ambient pressure, without the need for a vacuum chamber. It differs from low-pressure plasma (LPP) primarily in terms of operating pressure.

Key technical differences
Atmospheric pressure plasma processes are well-suited for inline processes and offer time advantages over low-pressure plasma processes.
In contrast, LPP processes are significantly more flexible in terms of process gas selection, making them ideal for uniform and ultra-fine plasma treatments, as well as for processing materials with complex 3D geometries.

You can learn more about plasma effects and the applications of low-pressure plasma systems in our informational article on our plasma technology.
For any further questions, simply contact our experienced team of experts.