| 摘要 |
<p>[PROBLEMS] Conventional Sn-Zn, lead-free solder pastes have disadvantages in that they are liable to form coarse Zn crystals of tens of micrometers in size and the formation of such coarse crystals can hardly be inhibited and that it is difficult to enhance the joint strength without changing the soldering temperature. Although an alloy improved in the strength by the addition of a slight amount of a group 1B element was developed, the alloy is disadvantageous in that it cannot reflow according to the same temperature profile as that of Sn-Pb paste because of its enhanced melting temperature. [MEANS FOR SOLVING PROBLEMS] A solder paste prepared by incorporating a powder of an Sn-Zn, lead-free solder paste with both an ethanol solution containing nanoparticles of 5 to 300nm in diameter containing at least one member selected from among Ag, Au and Cu and a flux forms, in soldering, an alloy consisting of Ag, Au and/or Cu and Zn and thereby forms fine clusters in the liquid phase, thus giving a fine solder texture after melting.</p> |
