Gold plated solder material and method of fluxless soldering using solder

摘要

A solder material 10 suitable for fluxless soldering attachment of a component 12 to a substrate 14 in a microelectronic assembly 16 such as a hybrid package comprises a core 18 and a gold layer 20 on the core. The core can comprise an alloy of tin and lead. The core preferably consists essentially of at least about 30 wt. % tin and the balance lead, so that it melts at temperatures of less than about 250° C. The gold layer is preferably applied to the core using an electroless plating process that forms a highly uniform gold layer. The solder material provides a joint between the component and the substrate comprising less than about 3 wt. % gold.