Magnetically aligned anisotropic conductive adhesive for high-frequency interconnects

An anisotropic conductive adhesive (ACA) is investigated for high-frequency interconnects. The ACA is created by aligning metal particles under a magnetic field during curing. Therefore, isolated thin columns of metal are created within the epoxy, allowing for the flow of current in only one direction. The thin columns form conductive paths between metal surfaces directly opposite each other in the z direction and not conduct in the x-y plane. In this manner, the epoxy can be used for interconnects without the need for patterning. This process is a low-temperature alternative to more traditional soldering technique, while also being lead free. A first example using this material as the interconnection of two-substrate through-bonded CPW lines. Both the high-frequency properties of this material and a demonstration of the interconnect performance are presented.