As electronic equipment has become smaller in size, printed circuit boards which cannot be subjected to cleaning have been developed, and a no-clean lead-free solder paste is becoming necessary. In order for a solder paste not to require cleaning, it is necessary that the color of the residue be transparent and that the residue be non-tacky. A maleated rosin, which is a rosin suited for no-clean paste, has a high acid value so it is not suitable for a flux for lead-free solder. As a means of suppressing a reaction between a flux containing a maleated rosin and a Sn-Ag-Cu based solder alloy powder, a Sn-Ag-Cu-Sb based solder alloy powder is used which adds 1 - 8 mass % of Sb to a Sn-Ag-Cu based solder alloy. As a result, it is possible to provide a solder paste which has the excellent effect that the solder paste does not easily undergo changes over time and
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