ELECTROMAGNETIC WAVE TRANSMISSION THROUGH LOSSLESS ELECTRICALLY CONDUCTIVE ADHESIVE

Abstract

We report our theoretical study on the electric conduction and the electromagnetic wave transmission between the IC chip and the substrate. The IC chip and the substrate are connected electrically by upper and lower contact shoulders which are conductively connected through an anisotropically conductive adhesive (ACA). It has been concluded that following the increase of the frequency of the electromagnetic field, the transmission of the electromagnetic field shifts from the conducting medium (metal) to non-conducting medium (adhesive) due to the skin effect. The DC electric conduction of the ACA is limited by the sizes, geometric shapes as well as spatial positions of metal fillers in the ACA. By excluding energy dissipation processes (because of the short distance between the upper and the lower contacts), our theoretical simulation indicates that the transmission of high-frequency (above 1 GHz when discussing the conduction properties of metal fillers having radius of no less than 5 μm) electromagnetic wave through the ACA is almost independent of the metal fillers because of the displacement current in the non-conductive medium between the upper and lower contacts.