Patent ID: 8961709
Filing Date: 2015-02-24
Classification: B23K,C22C,H05K

Abstract:
1. A lead-free solder paste comprising a first solder alloy powder of a first solder alloy, a second solder alloy powder of a second solder alloy, and a flux mixed with the first and second solder alloy powders, wherein the main peak temperature of the first solder alloy measured by differential thermal analysis is at least 10° C. lower than the main peak temperature of the second solder alloy measured by differential thermal analysis, the first solder alloy has a composition consisting of 3-4 mass % of Ag, 12-20 mass % of In, 0-1 mass % of Bi, and a balance of Sn, the second solder alloy has a composition consisting of 3-4 mass % of Ag, 0-1 mass % of Cu, 0-1 mass % of Bi, and a balance of Sn, and the overall composition after melting of the first and second solder alloy powders consists of 3-4 mass % of Ag, 3-10 mass % of In, 0-1 mass % of Bi, 0-1 mass % of Cu, and a balance of Sn.