Influence of substrate on electrical conductivity of isotropic conductive adhesive

Isotropic conductive adhesive (ICA) is widely used with different kinds of substrates in electronics packaging applications. Therefore it is necessary to understand the influence of electrical conductivity of ICA from substrate. In this work, we investigated the electrical resistivity of ICA on quartz, PCB and glass substrate. The experimental data showed that the in-plane electrical conductivity of ICA on PCB is almost twice that of the glass substrate, while the conductivity of ICA on quartz is also significantly greater than that of glass, under the same curing temperature and with the same bond line thickness (BLT) of ICA. This paper later concludes that thermal conductive adhesive (TCA) on substrate with higher thermal expansion coefficient (CTE) is likely to give better performance. Finally, Finite Element Modeling (FEM) and analysis shows that this phenomenon could be universal to ICA and TCA.