Effect of Surface Pretreatment and Plating Time on Electromagnetic Shielding Reliability of Electroless Plated Copper Layer Conductors

We have investigated the electromagnetic interference (EMI) shielding effect of copper conducting films prepared by electroless plating. The various EMI shielding films were made at different plating times (10, 20, 30, and 40 min). The influences of pretreatment and plating time on microstructure, thickness, adhesion (e.g., cross-cutting and pencil hardness), and electromagnetic shielding effectiveness were evaluated. The morphological features and thickness of EMI shielding films were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods. The experimental results show that the best outcome of adhesion and electromagnetic shielding effectiveness was obtained at the pretreated film with 30 min of plating time. The pretreated film showed a cross-cutting 5B grade, 4H pencil hardness, and 75 dB shielding effectiveness. The results of electromagnetic shielding effectiveness of films indicate that a longer plating time (10-30 min) results in better electromagnetic shielding effectiveness. However, the adhesive strength becomes worse if the plating time is longer than 40 min.