Adjustable EMI Shielding on Electronic Packages Realized by Electrolytic Plating

Abstract

As the electronic packages inside of smartphones and other handhelds further develop in terms of better performance and additional features/sensors, there are challenges rising up regarding the signal quality of each electronic package inside such a unit. The electromagnetic interference (EMI) shielding of electronic packages has to ensure the signal integrity on a high level. The demands of smartphone designers towards thinner and thinner units do further limit the footprint for a proper EMI shielding of the electronic package. EMI shielding like metal cans do not fit into the space requirements of modern smartphones. Therefore electronic package designers are investigating new ways of shielding electronic packages. New coating techniques of electronic packages like electroplating are investigated in order to realize an effective EMI shielding on electronic packages. This paper will describe the development work by a company specialized in electroplating in order to investigate the approach of electroplated EMI shielding. In comparison to other techniques like sputtering or conductive paste the plating on packaging level does offer the benefits of uniform plating thickness, the possibility to plate soft magnetic metal alloy layers, good coverage on the side walls of a package and finally cost benefits compared to other techniques. On selected packages two electroplated layers consisting of a high conductive metal layer and a soft magnetic metal alloy layer has been plated and investigated regarding their characteristics (coverage, thickness and adhesion). The paper will contain a description regarding plating process variations, layer characterizations and furthermore shielding performance test results carried out by IZM Fraunhofer.