Effective low-frequency EMI conformal shielding for system-in-package (SiP) modules

This letter presents several low-frequency electromagnetic interference shielding solutions by using the conformal shielding technology with the sputtering process. The shielding effectiveness (SE) is verified by the near-field test method with a transmission line (TL) as the radiating source. On the basis of the test condition and scenario, the TL-based modeling method is applied to quickly predict the SE performance. Detailed measurement environment, setup, and procedures are also thoroughly introduced in this letter. Four copper (Cu) solutions with 5, 10, 20, and 30 mu m shielding thicknesses and two hybrid copper/nickel-iron (Cu/NiFe) solutions with 5/5 and 13/5 mu m shielding thicknesses are tested. Among these solutions, a minimum of 15 dB and a maximum of 35 dB of measured SE at 10 MHz are seen. Moreover, the simulated and measured SE results are in good agreement. It is also noticed that the hybrid Cu/NiFe solution provides a comparable SE performance with a thinner thickness compared with the pure Cu solution.