Comparison chart low-pressure plasma/atmospheric-pressure plasma

Applications and propertiesAdvantages of low-pressure plasmaDisadvantages of low-pressure plasmaAdvantages of atmospheric-pressure plasmaDisadvantages of atmospheric-pressure plasmaAdvantages of atmospheric plasma coronaDisadvantages of atmospheric plasma corona
Plasma generation in generalPlasma is evenly distributed inside a plasma chamber. Chamber volumes can vary from 2 to 12,000 litres.Complex vacuum technology. In-line plasma treatment applications are limited.Plasma treatment can be realized directly at the conveyor belt. Suitable for in-line. No vacuum technology requiredThe plasma treatment track is limited due to the plasma excitation principle (approx. 8-12 mm). More nozzles must be used for the treatment of larger objectsPlasma treatment can be realized directly at the conveyor belt. Suitable for in-line. No vacuum technology required. The plasma treatment width is approximately 60 mm.Only suitable for non-conductive substrates. Relatively low treatment rate compared with atmospheric-pressure plasma
Treatment of metalsOxidation-sensitive objects can be cleaned with plasma. (e.g. H2 as process gas)The energy can be coupled to the objects by microwave excitation. This causes overheating of the object. With kHz plasma no overheating is observedIn plasma treatment of aluminium, very thin oxide layers (passivation) can be generatedThe plasma cleaning of oxidation-sensitive objects is limitedNot possible
Treatment of polymers/elastomersPlasma activation of PTFE is possible (etching process). Good plasma processes for elastomer and PTFE seals have been developed and are in useSome materials (e.g. silicone) require larger pumps to achieve the required process pressurePretreatment of "endless" objects is possible (e.g. hoses, cables, etc.). Very short process timePlasma jet has a temperature of approx. 200-300 °C. Process parameters must be well adapted to the surface to avoid combustion (thin materials)Pretreatment of "endless" and wide objects (up to 60 mm) is possibleRelatively low treatment rate compared with atmospheric-pressure plasma. The treatment uniformity and the surface energy are somewhat lower in comparison with atmospheric and low-pressure plasma
3-D objectsAll objects in the plasma chamber are treated equally. Even cavities can be treated from the inside (e.g. ignition coils, water tanks, etc.)Not knownLocal surface treatment is possible (e.g. adhesive groves)Elaborate articulated robot technology is required. Gap penetration properties of atmospheric-pressure plasma is limitedOnly conditionally suitableElaborate articulated robot technology is required. Gap penetration properties of the corona plasma is very limited
Bulk material itemsRotary drum method allows uniform plasma treatment of bulk material items. The number and volume of parts may be variable Only 1/3 of the rotary drum volume is used (recommended)The objects can be treated directly on the conveyor beltThe objects have to be very accurately positioned on the conveyor beltThe treatment of bulk material items in conjunction with a rotary drum is possible. The parts can be treated directly on a conveyor belt (3-dimensional)Reduced treatment intensity compared with low-pressure plasma
Electronic/semiconductor technologyPlasma treatment of electronic components, circuit boards and semiconductor parts by means of low-pressure plasma is state of the art.Not knownPlasma pretreatment of metal or ITO contacts must be implemented immediately before the bonding process (e.g. LCD, TFT and chip production)Increased temperature of the plasma jet and limited gap penetration properties may limit the use of atmospheric-pressure plasma in the electronics industryNot suitable due to high voltage potential
Coating processesProduction of uniform coatings. Many PECVD and PVD processes have been developed and are appliedPlasma chamber may be contaminatedThere are many applications used in industryThere are currently no applications used in industryThere are currently no applications used in industry