Optimization of the NiFe/Cu multilayer structure using magnetron sputtering for electromagnetic interference shielding in high-frequency bands

In this study, NiFe/Cu multilayer structures were fabricated using a sputtering method. The electromagnetic interference shielding effectiveness (EMI SE) of symmetrical and asymmetric structures of 4 μm NiFe/Cu multilayers was evaluated to optimize their performance. In addition to the number of layers, a decrease in the electrical conductivity of each Cu layer led to a decrease in the EMI SE. In the multilayer structure with a 100 nm NiFe layer, an EMI SE ranging from − 75 to − 73 dB was obtained in the wideband owing to the increase in the thickness of each Cu layer within the multilayer. In contrast, when the thickness of the NiFe layers was 500 nm, the improvement in the EMI SE was negligible owing to the decrease in the electrical conductivity difference between the NiFe and Cu layers.