Hygrothermal Durability of Hybrid Electrically Conductive Adhesive at Optimal Micro-nano Fillers Ratio

While numerous researchers have successfully established hybridHybrid electrically conductiveConductive adhesive (HECA) as a polymer-based interconnector in electronic packaging, the longevity of developed technologies is at stake since there is minimal explanation in the literature regarding the performance in a severe thermal and humid climate. This paper evaluates the HECA reliability formulated with different micro-nano ratios of silver micro-flakes and multiwalled carbonCarbon nanotube (AgMF-MWCNT) at a low range from 0.07 to 0.27, by applying hygrothermal exposure under 85 °C and 85% relative humidity for 3 weeks of the ageing period. Water absorption, electrical, mechanical, and morphological analysis were conducted via gravimetric measurement, four-point probe test, lap shear test, scanning electron microscopy (SEM), and visual observation, respectively. Volume resistivity and water absorption behaved anomaly with no deterioration. Still, they improved electrical performance due to shrinkage behaviour as evidenced by SEM, while weight loss is associated with accelerated hydrolysis reaction in epoxy upon high-temperature moisture attack. Furthermore, lap shear strength deteriorated gradually in the first week, suggesting the epoxy degradation behaviour. However, unlike ECA, the secondary curing phenomenon partially recovers the HECA's strength towards a more extended ageing period. Overall, the 0.17 ratio provides optimal reliability in all aspects considered.