Lead-free solder alloy and solder reflow process

A lead-free solder alloy consisting essentially of, by weight, 3.0% to 3.5% silver, greater than 1% to about 15% copper, the balance tin and incidental impurities, and having an effective melting range of about 215° C. to about 222° C. The solder alloy is noneutectic, and therefore characterized by...

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Bibliographische Detailangaben
Hauptverfasser: CARTER BRADLEY H, MELCHER CURTIS W, YEH SHING
Format: Patent
Sprache:eng
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Zusammenfassung:A lead-free solder alloy consisting essentially of, by weight, 3.0% to 3.5% silver, greater than 1% to about 15% copper, the balance tin and incidental impurities, and having an effective melting range of about 215° C. to about 222° C. The solder alloy is noneutectic, and therefore characterized by solidus and liquidus temperatures, the former being in a range of about 215° C. to about 218° C., while the latter is about 290° C. or more. However, the melting mechanism exhibited by the alloy is such that the alloy is substantially all melted and does not exhibit a "mushy zone" above the effective melting range, enabling the alloy to behave similarly to the SnAgCu eutectic alloy.