Magnetically Aligned Anisotropic Conductive Adhesive for Microwave Applications

Randomly dispersed particles in a material can be forced to align due to the presence of an externally applied field. These self-aligning materials are examples through which order is obtained through structure created internally which alters the bulk properties of the material. One such material is a magnetically aligned anisotropic conductive adhesive which uses the alignment of ferromagnetic particles in order to create current flow in only one direction. This paper discusses microwave application of such a material. We demonstrate that the magnetically aligned
Z
-axis anisotropic conductive adhesive works at microwave frequencies interconnecting silicon substrates through 90 GHz. The
Z
-axis material is found to be a suitable replacement for solder bumping even at high frequencies of operation. The effect of material composition and the radio frequency design is discussed in this paper. Finally, the
Z
-axis anisotropic conductive adhesive is found to be a suitable cost-effective replacement for solder bumps at high frequencies.