Nordson MARCH has revealed that recent studies have indicated that Printed Circuit Boards (PCBs) feature improved coating adhesion when plasma treated prior to conformal coating. Enhancing surface wettability, the plasma treatment improved adhesion of the conformal coating to high-performance solder mask materials and other difficult-to-adhere-to substrates.
While it can be difficult to apply adequate coating to some materials meeting strict environmental requirements, such as RoHS, the flow characteristics of the conformal coating material improved when the PCB was treated with plasma. Only nominal plasma process conditions are required for enhanced adhesion (as little as 30 seconds).
Contaminants such as mold release compounds and residual flux can also create additional challenges for conformal coating adhesion. By removing the contaminants without damaging the substrate, plasma treatment is an effective way to clean the boards in these cases.
Applications for plasma treatment include adhesion improvement, conformal coating, surface activation, plasma cleaning and etching.