High frequency measurement of isotropically conductive adhesives

Isotropic conductive adhesives (ICAs) have some distinct advantages over SnPb solders as interconnect materials. With the increasing frequency applied in electronics, the electrical properties of ICAs at high frequency need to be investigated. A flip-chip test vehicle is designed and manufactured. FR-4 board is used as the substrate and gold plate copper as the transmission line. SnPb solder paste and ICA are applied using stencil printing and assembled. A network analyzer is used to study the signal reflection and transmission of the test vehicles. Results show that there is no significant difference between ICA joints and SnPb joints in the frequency range from 45 MHz to 2 GHz before aging. After 150 hours of aging, the S₁₂ values of SnPb interconnects deviated more than the ICA interconnects. High-frequency substrate is needed in order to investigate the characteristics of ICA and SnPb solder at a higher frequency range