Low temperature-cured electrically conductive pastes for interconnection on electronic devices

Highly conductive pastes were prepared by thermal sintering of silver particles into a polymer matrix. These electrically conductive pastes are composed of a novolac epoxy resin and a trimodal metallic mixture of micron-sized silver flakes, silver microspheres, and silver nanoparticles and can be cured at relatively low temperatures. Our strategy is to cure the epoxy resins at a higher temperature than the sintering temperature of the silver powders to form a good metallic network of the conductive materials. We found that our epoxy-based conducting pastes had a low volume resistivity and high electrical conductivity of 8.9 × 10−6 Ω cm and 1.1 × 105 S cm−1, respectively, even at a low curing temperature of 250 °C. The resulting high conductivity may be attractive for numerous applications in various optoelectronic devices that require low-temperature processing.