Au-sn alloy powder for solder paste

摘要

The problem is to provide an Au-Sn alloy powder for use in producing an Au-Sn alloy solder paste having reduced generation of voids. The problem is solved by an Au-Sn alloy powder for a solder paste, which has a composition consisting of Sn of 20.5-23.5% by mass and a remainder containing Au and inevitable impurities, and which has a microstructure in which 0.5 to 30 area % of fine Sn-rich primary crystal phase regions having a diameter of 3 mum or less are crystallized in a matrix.