Abstract:
In an electronic package, a solder connection (14) for bonding faying surfaces (31, 40) is formed of tin-bismuth alloy comprising a tertiary metal, preferably gold or silver, in an amount effective to increase the melting temperature of the alloy and enhance mechanical properties of the connection at elevated temperatures typically encountered during operation. A process for forming the solder connection comprises applying a film (36) of the tertiary metal onto at least one faying surface (31) and thereafter applying tin-bismuth solder paste (38) onto the film. Preferably, a plate (26) of tin-bismuth alloy is first electroplated onto the faying surface (31), onto which the tertiary metal is plated. During heating to reflow the solder, the tertiary metal dissolves to produce a uniform liquid that forms the connection.
Abstract:
In an electronic package, a solder connection (14) for bonding faying surfaces (31, 40) is formed of tin-bismuth alloy comprising a tertiary metal, preferably gold or silver, in an amount effective to increase the melting temperature of the alloy and enhance mechanical properties of the connection at elevated temperatures typically encountered during operation. A process for forming the solder connection comprises applying a film (36) of the tertiary metal onto at least one faying surface (31) and thereafter applying tin-bismuth solder paste (38) onto the film. Preferably, a plate (26) of tin-bismuth alloy is first electroplated onto the faying surface (31), onto which the tertiary metal is plated. During heating to reflow the solder, the tertiary metal dissolves to produce a uniform liquid that forms the connection.
Abstract:
In an electronic package, a solder connection (14) for bonding faying surfaces (31, 40) is formed of tin-bismuth alloy comprising a tertiary metal, preferably gold or silver, in an amount effective to increase the melting temperature of the alloy and enhance mechanical properties of the connection at elevated temperatures typically encountered during operation. A process for forming the solder connection comprises applying a film (36) of the tertiary metal onto at least one faying surface (31) and thereafter applying tin-bismuth solder paste (38) onto the film. Preferably, a plate (26) of tin-bismuth alloy is first electroplated onto the faying surface (31), onto which the tertiary metal is plated. During heating to reflow the solder, the tertiary metal dissolves to produce a uniform liquid that forms the connection.