Research on conformal EMI shielding Cu/Ni layers on package

Electromagnetic noise caused by high speed digital and radio frequency electronic devices can affect the normal operation of other devices within the same system and result in significant intra-system electromagnetic interference (EMI) problems. Conformal shielding is an emerging method to prevent EMI by using metallization techniques to coat a thin metal layer around the package. In this study, copper is used as the main shielding material due to its excellent conductivity and low price. A nickel layer is plated over copper to protect the oxidation of copper. We focus on the effect of electroless plating process on adhesion and the influence of Cu/Ni thickness on shielding effectiveness. As a result, swelling for 15 minutes and etching for 5 minutes can lead to best adhesion. When copper thickness increases, shielding effectiveness first increases and then remains at a certain level. Changing nickel thickness has very little impact on shielding effectiveness.