The challenge: complex geometries
The plasma treatment of plane and at the same time partially complex geometries such as low-lying grooves, cavities or undercuts represents a particular challenge. Expensive array arrangements of plasma jets or complicated combination solutions are often unavoidable.
An effective and low-cost alternative has been developed at the Fraunhofer IST: the core of the new plasma source concept is a jet-induced, dielectrically impeded sliding discharge which even allows the effective activation or functionalization of geometrically challenging contours.
The operating principle of the new jet
Inside the innovative sliding discharge plasma jet, a cold plasma is first ignited by means of alternating voltage. This is guided via the process gas flow around the internal electrode out of the middle of the nozzle and onto the external earth electrode on the underside of the source. As a result of direct discharge between the internal and external electrode, discharge filaments are formed between them which adapt perfectly to the contours of the substrate surface. The homogeneous sliding discharge produced allows an even and complete treatment of the surface, including any possible recesses or cavities. Depending on the type of source and distance of the source from the substrate (1 - 40 mm), effective bandwidths of between 10 and 120 mm are possible.