Abstract: A solder composition that bonds well to oxides and other surfaces to which solder bonding is conventionally difficult is provided. The solder is particularly useful for reliable bonding and packaging of optical components that often have oxide surfaces. The solder composition exhibits a microstructure containing a solder matrix in which is distributed fine, micron-scale islands of rare-earth-containing intermetallic particles. The existence of the islands makes the rare earth elements better available for bonding, and reduce the extent to which the rare earths are oxidized. Advantageously, the solder contains Au and/or Ag, in which the rare earth elements tend to have some solid solubility. Due to this solubility, the Au and/or Ag tend to provide some additional protection of the rare earths against oxidation, and thereby also provide accelerated dissolution of the rare earth into the molten solder.

Abstract: A method of electrically connecting a semiconductor package to a substrate by using bump contacts formed by heating the tip of an alloy wire and directly joined to aluminum alloy wiring lines, an alloy wire for such a purpose, and a semiconductor device constructed by electrically connecting a semiconductor package to a substrate by such a method. The alloy wire is produced by drawing an alloy material produced by quench solidifying an alloy containing Pb, Sn or In as a principal element, and an additive element or additive elements. The tip of the alloy wire is heated to form a ball to be joined to the aluminum alloy wiring line as a bump contact. The Brinell hardness number of the ball is H.sub.B 6 or higher.