Development Of Middling Temperature Curing Isotropic Conductive Adhesive For Electronic Packaging Interconnection

After simple introduction of isotropic conductive adhesive (ICA), which was a new lead-free electronic packaging material, two parts of work with respect to ICA development and research were presented. One was Ag filled conductive adhesive development. The other was Ag plating Cu powers development for ICA and the preparation of Ag plating Cu powers filled conductive adhesive. A kind of Ag filled conductive adhesive was successfully developed with property right. Firstly, all of the Ag filled conductive adhesive materials was introduced and a detailed rule for every material selection was put forward. Secondly, the only proportion was designed through intercross experiment. The result was that epoxy: hard: accelerant equal to 100: 85:0.5 for resin. Thirdly, the best Ag (5 μm～8 μm) filled amount 72% was obtained by experiment. Lastly, the performance of Ag filled conductive adhesive was optimized through adding additives. KH-550 could improve the Viscosity of Ag filled conductive adhesive. SYNTHRON could reduce inanition and TNPP was able to prevent aging of Ag filled conductive adhesive. Conductivity, curing process and shear strength of Ag filled conductive adhesive were tested. The testing ways of electricity were direct measure method and four probes method. Different Scanning caloric (DSC) analyzed the curing process of Ag filled conductive adhesive and the shear strength was tested through REGER instrument. At the same time the relation of the amount of hard and accelerant to some Ag filled conductive adhesive performances. The amount of accelerant would effect the using and hard time of ICA. The using and curing time decreased with the increasing of accelerant amount. The amount of hard would effect the strength of ICA. When the amount of hard was the best proportion to epoxy, the intension of ICA was the highest. At last, we researched the size and shape of Ag powers. The result was that the flake Ag power can have the biggest contacting area and the resensity of ICA was the lowest. While the size of Ag powers was 2 micrometer to 8 micrometer, the resensity of ICA could be under 10-4 ?.cm. A micro-flake copper powder was obtained by grinding commercial copper powder. With several electroless plating silver treatments to the micro-flake copper powder, a high performance copper powder covered with more than90% surface with silver was obtained. A kind of conductive adhesive consists of above copper powder, epoxy resin, harder and other additives was synthesized, which can prevent copper powder's oxidation effectively. In addition, it has a stable resistance and the resistivity could be less than 8.5×10-4 ?.cm. Compared with silver conductive adhesive, it has lower cost and better to bear electronmigration. This kind of ICA material would have the widest researching worthiness.