The Sn-Pb solder widely used in the traditional electronic packaging industry has exposed its disadvantages, such as too high solder welding temperature, easy to damage devices, too low line resolution, unfriendly to the environment and so on. The ECA has the advantages of environmentally friendly, less processing steps, narrow processing width and low temperature, which has attracted widespread attention [1–4]. The ECA is the main substitute for Sn-Pb solder and has become an indispensable new material in the electronic industry [5–7]. In order to enhance the adhesion and conductivity of ECA, conductive fillers, curing agents, diluents and promoters are added to the matrix resin. Conductive fillers provide conductive ability for ECA, so the performance of fillers can greatly affect the conductive performance of the composites. The conductive fillers of ECA are mainly include metal powders, graphite, carbon nanotubes [8–14]. The metal filler has good conductivity and usually include silver, copper, gold, chromium, nickel and lead-free alloy. The silver is widely used because of its good electrical conductivity, moderate price and strong antioxidant properties. Compared with micron scale silver powder, silver nanopowder has the characteristics of large specific surface area, high surface energy and high chemical reaction activity [15–22]. At present, high dispersion silver nanopowder is mainly prepared by electrolysis, spray pyrolysis, chemical reduction and DC arc plasma evaporation under atmosphere protection. The silver nanopowder prepared by vacuum DC arc plasma method has high purity and high yield. Matrix resin plays a role in providing polymer skeleton and bonding strength in ECA. Matrix resin mainly includes epoxy resin, polyimide, phenolic resin, silicone and thermoplastic. Epoxy resin has strong bonding force, stable performance, high transparency corrosion resistance. Although ECA have many advantages and are widely used, compared with metal solders, they are still in the immature stage of technology, and there are many technical problems to be solved, such as poor mechanical properties, large volume resistivity, poor thermal conductivity, etc. This paper mainly studies the mechanical and electrical properties of isotropic conductive adhesive to narrow the gap between isotropic conductive adhesive and metal solder.
In this experiment, highly dispersed and nearly spherical silver nanopowder was prepared by vacuum DC arc plasma method. It was applied to isotropic conductive adhesive, printed on different substrate, and then cured at low temperature to prepare conductor. The effects of conductive filler content on conductor resistivity and shear strength were systematically studied.