Inventors:
Shing Yeh - Kokomo IN
Bradley H. Carter - Kokomo IN
Frank Stepniak - Noblesville IN
Scott D. Brandenburg - Kokomo IN
Assignee:
Delphi Technologies, Inc. - Troy MI
International Classification:
B23K 3526
US Classification:
428647, 428620, 428674, 2282629, 2282622
Abstract:
A tin-lead solder alloy containing copper and optionally silver as its alloying constituents. The solder alloy consists essentially of, by weight, about 55% to about 75% tin, about 11% to about 44% lead, up to about 4% silver, nickel, palladium, platinum and/or gold, greater than 1% to about 10% copper, and incidental impurities. The solder alloys contain a small portion of CuSn intermetallic compounds, and exhibit a melting mechanism in which all but the intermetallic compounds melt within a narrow temperature range, though the actual liquidus temperature of the alloys may be considerably higher, such that the alloys can be treated as requiring peak reflow temperatures of about 250Â C. or less. The intermetallic compounds precipitate out to form a diffusion barrier that increases the reliability of solder connections formed therewith.