Solder Preform and Method of Sealing
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
In using solder preforms to form a solder seal in package applications, the failure to properly wet a solderable surface may result in defective seals. This laminated solder preform 10 has a layer 12 (10% Sn-90% Pb) joined to a layer 14 of pure Sn. The relative thicknesses of layers 12 and 14 are adjusted so that the overall composition of the preform is 60% Sn-40% Pb. The improved wettability of the laminated preform may be due to the fact that it melts over a range of temperatures, instead of a single temperature, as with 60% Sn-40% Pb solder. Preforms of various compositions and thicknesses may be useful in other applications for which a low melting eutectic is required as the end result.