Delphi Technologies, Inc.

Delco Electronics Corporation

Curtis Wayne Melcher

Shing Yeh

Bradley H Carter

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&deg; C. to about 222&deg; C. The solder alloy is noneutectic, and therefore characterized by solidus and liquidus temperatures, the former being in a range of about 215&deg; C. to about 218&deg; C., while the latter is about 290&deg; 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 &ldquo;mushy zone&rdquo; above the effective melting range, enabling the alloy to behave similarly to the SnAgCu eutectic alloy.

Lead-free solder alloy and solder reflow process

A lead-free solder alloy suitable for forming solder joints of a surface-mount integrated circuit device, such as a flip chip. The solder alloy has a sufficiently low liquidus temperature to achieve desirable reflow properties at temperatures of 240.degree. C. and less, and is therefore compatible with integrated circuit processes. The solder alloy has a sufficiently high solidus temperature to ensure that solder joints formed with the alloy exhibit suitable mechanical properties at application temperatures up to 150.degree. C. when mounting a component to a laminate substrate. The solder alloy generally contains, in weight percent, about 7 to about 11% indium, about 2.5 to about 3.5% silver, and about 0.5 to about 1.5% copper, the balance tin and incidental impurities.

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Kokomo, IN, United States of America

Curtis Wayne Melcher