A practical guide on the use of electroless coatings for EMI shielding

Over recent years there has been an increasing trend to replace metals with plastics in the manufacture of computers, business and industrial machines, automotive and telecommunications components and other electronic equipment. Economics is usually the driving force due to the trend toward miniaturisation and more complex designs. A consequence of taking advantage of the full function design flexibility of plastics is increased susceptibility to EMI/RFI due to the inherent dielectric nature of the plastic itself. It has been necessary therefore, to develop shielding techniques to protect the sensitive electronic devices from any external interference while at the same time preventing any interference being emitted from the device to adversely react with other adjacent equipment. In selecting the correct shielding technology several key issues must be considered, coating uniformity, resistance to environmental exposure as well as shielding capability. Electroless coatings are now one method extensively used as an effective shield on plastic substrates. This paper discusses the practical use of electroless coatings to meet EMC regulations