COMPOSITE FILM FOR BOARD LEVEL EMI SHIELDING

摘要

An EMI shielding composite film for use in printed circuit boards has at least two layers, a top layer electrically conductive in all directions (isotropic), and a bottom layer electrically conductive only in the Z (thickness) direction (anisotropic) after thermo-compression. The bottom layer is in contact with the grounding pads of the circuitry of the electronic device to be shielded. The conductive top layer functions similarly to metallic boxes to prevent the electromagnetic radiation from both entering the boxes and escaping into the environment. The bottom layer interconnects the top conductive layer to the grounding pads on the PCB after thermo-compression so that electromagnetic waves collected by the top layer are directed and released to PCB grounding pads through the bottom layer.