Patent 7686982 was granted and assigned to Asahi Kasei on March, 2010 by the United States Patent and Trademark Office.
Disclosed is a conductive filler which can be fusion-bonded under lower temperature conditions (with the peak temperature of not less than 181° C.) than the reflow heat treatment conditions for an Sn-37Pb eutectic solder. This conductive filler is applicable to heat-resistant uses similar to those of the Sn-37Pb eutectic solder. The conductive filler is a mixture of first metal particles composed of an alloy having a chemical composition including 25-40% by mass of Ag, 2-8% by mass of Bi, 5-15% by mass of Cu, 2-8% by mass of In and 29-66% by mass of Sn, and second metal particles composed of an alloy having a chemical composition including 5-20% by mass of Ag, 10-20% by mass of Bi, 1-15% by mass of Cu and 50-80% by mass of Sn. In the mixture, 20-10,000 parts by mass of the second metal particles are contained per 100 parts by mass of the first metal particles.