Plasma Treatment for Printed Circuit Boards
As the substrate for electronic components, printed circuit boards are partially conductive. Until now, this has meant that atmospheric procedures could not be used to process printed circuit boards. Any pretreatment method that even comes close to conducting electrical potential creates shorts resulting in the destruction of layout and components.
New Possibilities for Sensitive Electronic Applications
With these types of electronic applications in mind, plasma jets developed by Openair-Plasma® work with zero voltage* input to the component. This unique feature of Openair-Plasma® treatment opens up possibilities for a whole range of industrial applications.
*For selected jet combinations in specific applications, the residual potential is <0.1 volts.
ADVANTAGES &
PROPERTIES
of Openair-Plasma® treatment for printed circuit boards:
- Potential-free surface treatment (e.g., super-fine printed circuit board cleaning)
- Makes new, more efficient process architectures feasible
- Eliminates whole production lines in the manufacturing process
- Makes it possible to selectively activate plasma in electronic components.
Improving the quality of SMD assemblies in the avionics industry
The safety requirements for avionics are far more rigorous than those of other industrial products. Assembled circuit boards, for instance, are required to undergo burn-in, which is regarded as the toughest stress test available for electronic components. It is used to detect hidden manufacturing faults and to identify components which would fail in continuous operation.
Components treated with Openair® plasma survive the burn-in test
Before undergoing the burn-in test, the plastic-coated SMDs of aeronautical radio equipment are pretreated with Openair-Plasma® to ensure the long-time stable adhesion of the conformal coating.The results show not only that the highly sensitive electronics survive the plasma exposure completely unscathed; the potential-free plasma treatment also enhances product quality.
Furthermore, this combined effect of microfine cleaning and activation reduces the number of individual operations required, which makes for a more efficient production process.
Interesting success stories in this field
Plasma surface activation - Printing circuit boards with resistor paste
To get secure adhesion and good electrical characteristics from resistors printed on a circuit board, the surface tension of the component must be greater than that of the ink, or in this case of the resistor paste.
Openair-Plasma® has produced this surface activation for years now in the inline process for manufacturing safety-related sensors for the automobile industry. Plasma treatment ensures permanent ink adhesion at the highest standard.
Abrasive Plasma – Alternative Procedure to Clean Drilled Holes (Desmearing) in Printed Circuit Boards
Drilled hole cleaning is an important step in printed circuit board processing prior to through-hole plating. Until now, this step was performed mainly in elaborate chemical or low-pressure plasma procedures that required interrupting the manufacturing process with separate chamber systems. In contrast, desmearing using the inline Openair-Plasma® process is done in atmospheric conditions, which simplifies and accelerates the relevant process and reduces costs as well.
Especially in conjunction with the use of industrial gases, the Openair-Plasma® process can form a strongly abrasive plasma that provides outstanding selectivity and high removal rates. The first installations of this new plasma technology are now in the preparatory stages.
Strong Adhesion of Multiple Layers using Openair-Plasma® Activation
Flexible printed circuit boards are now indispensible, especially in today’s mobile electronics. And flexible printed circuit boards are more and more frequently constructed of multiple layers due to the constantly increasing circuit component density. Firm adhesion is critical for trouble-free functioning of multiple-layer structures.
The adhesion between the individual layers is significantly improved with Openair-Plasma® activation. Since this often involves large-scale applications, systems with RD1010 plasma jets are used. The leading Japanese manufacturer of printed circuit board manufacturing equipment, Hitachi, offers this jet technology in its systems.
