Prefabricated and Assembled Electromagnetic Shields Inside Electronic Packages to Reduce Near-Field Capacitive and Inductive Coupling

Electromagnetic shielding often requires the integration of thick shielding structures in the form of metal casings, walls, or via arrays. These shields typically isolate the entire package from external or internal noise sources. In some cases, they also isolate components within the package. However, integration of shielding structures with the required performance creates miniaturization and fabrication constraints, and results in longer product development cycle times. To address these limitations, a novel approach is presented for component- and package-level shielding. This approach is based on electromagnetic interference (EMI) shield integration through a microassembly of prefabricated shields inside microslots in packages and printed circuit boards (PCBs). This approach eliminates many of the design and process constraints during the shield integration within packages. Various design options were considered to mitigate capacitive and inductive coupling between representative microstrip lines that act as aggressors and victims. Three types of EMI shielding architectures, U-shaped, inverted-L-shaped, and T-shaped, were investigated with 17.5 μm copper. The fabricated EMI shields were studied for their shield performance, both as a compartmental shield between specific components and as a conformal shield from external and internal noises. The role of the ground termination was also investigated to further optimize the shielding performance.