Solder cream and method of soldering electronic parts

摘要

The present invention aims at providing a high-temperature lead-free solder material which can form a solder joint of improved heat resistance and reliability, and is suitable for application to dual-temperature solder connection, and a method of soldering an electronic part. According to the invention a solder cream is obtained by kneading an Sn-Ag-Cu alloy with a flux, wherein the Sn-Ag-Cu alloy comprises a mixture of a first powder alloy containing 10 to 30% by weight of Ag and 2 to 20% by weight of Cu with a balance consisting of Sn and unavoidable impurities, and a second powder alloy containing smaller compositions (% by weight) of Ag and Cu than the first powder alloy, and having a melting point lower than that of the first powder alloy, the mixture containing a total of not more than 35% by weight of Ag and Cu.