Improvement of adhesion and electrical properties of reworkable thermoplastic conductive adhesives

The adhesion and electrical properties of a PAE-2-based isotropically conductive adhesive (ICA) material were investigated. PAE-2 (thermoplastic polymer)-based ICAs, as well as a commercial epoxy-based ICA, showed dramatic reduction in adhesion to a NiAu surface after the 85degreesC/85% RH aging test, while the adhesion to a SnPb surface did not change much. To improve the adhesion strength of PAE-2 to a Ni:Au surface after the humidity aging test, coupling agents and epoxy blends were used. The formulation with a higher amount of epoxy showed a higher adhesion strength. The combined use of epoxy blending and coupling agents was effective in increasing the adhesion strength of PAE-2 before aging and also in maintaining adhesion at a 50% level after humidity aging. However, its adhesion strength to NiAu was reduced to less than 50% after 85degreesC/95% RH aging. PAE-2-based ICAs showed excellent reworkability.