EMI Shielding by Plating Technique and Its Performance on the Shielding Effectiveness

Abstract

In the effort to miniaturize the electronic packaging, plating on mold compound has been in intensively studied as a solution to replace the metal can for Electro-Magnetic Interference (EMI) shielding. Plating technique is capable to reduce 5 to 10 times space compare to the metal can. A pre-shielded package can be done by plating in an array form before send to the die cut. This will enable shielding in bulk hence reduce the manufacturing foot print and cost. In our past research work, we had demonstrated a feasible manufacturing process, and the plated product had reached the high reliable performance [1]. Following the research, we design a series of microstrip patch antennas to evaluate the effectiveness of EMI shielding by the plating technique, in frequency of 2.65, 6.26 and 10.0GHz. Antennas are coated with conformal coat ink as the insulator, followed by plating of the nickel-phosphorous (NiP) and the pure copper (Cu). The capability of plated metal shield to attenuate the antenna receiving power, is used to evaluate the performance of EMI shielding effectiveness (SE). Result showed a direct co-relation of the metal thickness towards EMI shielding effectiveness, but it come into saturation when we further increase the thicknesses. Besides, test also shown material selection on copper versus nickel-phosphorous with its high differences on conductivity and permeability properties, resulting in different EMI shielding performance at different frequency. The combination of 2 different metals enhance the EMI shielding result compare to single metal