A SOLDER ALLOY FILLED Z-AXIS CONDUCTIVE EPOXY ADHESIVE

Epoxy adhesives filled with four different volume fractions of eutecti c tin-bismuth solder alloy were prepared and the effect of filler cont ent on the electrical and mechanical properties of these anisotropic e lectrically conductive adhesives was investigated. The results show th at the adhesive containing the lowest amount of the filler alloy had t he best combination of conductivity, insulation resistance and shear s trength. The DSC-measurements suggested that the filler melts before t he cure of the resin begins which allows the filler to wet and bond we ll to the conductors. This was verified by SEM/EPMA examinations. A te mperature cycling test and high humidity, high temperature treatment w ere conducted on the best composite adhesive. The temperature variatio n had no effect on conductivity of the joints while humid and hot envi ronment decreased the conductivity.