Lead-free solder alloy

Abstract

Provided is a lead-free solder alloy that has excellent tensile strength and ductility, does not deform after heat cycles, and does not crack. The In and Bi content are optimized and the Sb and Ni content are adjusted. As a result, this solder alloy has an alloy composition including, by mass, 1.0 to 7.0% of In, 1.5 to 5.5% of Bi, 1.0 to 4.0% of Ag, 0.01 to 0.2% of Ni, and 0.01 to 0.15% of Sb, with the remainder made up by Sn.

1 - 6 . (canceled) 
     
     
         7 . A lead-free solder alloy having an alloy composition comprising: 1.0 to 7.0 wt % of In, 1.5 to 5.5 wt % of Bi, 1.0 to 4.0 wt % of Ag, 0.01 to 0.2 wt % of Ni, 0.01 to 0.15 wt % of Sb, and a balance of Sn. 
     
     
         8 . The lead-free solder alloy according to  claim 7 , wherein In is incorporated in an amount of 1.0 to 6.5 wt % and Bi is incorporated in an amount of 2.5 to 4.0 wt %. 
     
     
         9 . A solder paste comprising the lead-free solder alloy according to  claim 7 . 
     
     
         10 . A solder paste comprising the lead-free solder alloy according to  claim 8 . 
     
     
         11 . A preform material comprising the lead-free solder alloy according to  claim 7 . 
     
     
         12 . A preform material comprising the lead-free solder alloy according to  claim 8 . 
     
     
         13 . A solder joint comprising the lead-free solder alloy according to  claim 7 . 
     
     
         14 . A solder joint comprising the lead-free solder alloy according to  claim 8 . 
     
     
         15 . An in-vehicle electronic circuit comprising the solder joint according to  claim 13 . 
     
     
         16 . An in-vehicle electronic circuit comprising the solder joint according to  claim 14 .