PURPOSE: To drastically decrease the chip rising of microparts such as QFP by using a solder powder material formed by coating 10Sn-90Pb to be used as a nucleus with 96.5Sn-3.5Ag of the m.p. lower than the m.p. thereof as a solder material.

CONSTITUTION: The cream solder material formed by using the solder powder material obtd. by coating the 10Sn-90Pb to be used as the nucleus with the coating layer of the 96.5Sn-3.5Ag of the m.p. lower than the m.p. thereof, by which the coating layer is first melted at the time of reflow, then the nucleus is melted and both are mixed to form the molten solder of the compsn. 62Sn-36 Pb-2Ag and the solder is gradually melted. The chip rising defect generated from the rapid melting of the solder is thereby eliminated. Since the cream solder material formed by using the solder powder material consisting of two layers having 5 to 15μm grain size of the nucleus is used, the sufficient dealing with the QFP of 0.3mm pitch is possible.