Manufacture Of Gold-Tin Solder Foil Used In Optoelectronic Package

Au-Sn solder, a kind of precious metal solder, is often used in optoelectronic package and military electronic module with high reliability. Melt point of the solder with 20%Sn and the balanced Au is very small and this component point is a eutectic point. Au-Sn solder has large strength, fine ant-oxidation, small melt point, low liquidity, excellent heat fatigue and creep deformation resistant. These merits makes Au-Sn solder to be one of the perfect solders used in optoelectronic package. But it's so fragile that can't be manufactured by normal method. Its high price and difficult manufacture inhibit its own development, so it's attracted more and more attention by many scholars from different countries.This text reveals tow methods, gold and tin lamination method and alloy method, to make perfect Au80Sn20 solder foil with all kinds of thickness. The manufacture method of AuSn20 solder foil is researched by pre-producing AuSn20 solder ring with 1.0mm external diameter, 0.4mm internal diameter and 0.4mm thickness which has fine dimensional accuracy and excellent component. Lamination method is applied by using the diffuse between Au foil and Sn foil which laminates Au and Sn with a ratio-80:20, afterward rolling solder foil which has the required specification. The solder foils which are produced by the former method bear fine ductibility to be in favor of continued processing and punching. This solder has fine ductility, and benefit after process and blanking. Alloy method is that foundry of AuSn20 alloy, heat rolling and heat treatment make solder shaped with different thickness and minimize solder's brittleness, then accepted AuSn20 solder ring is made by designing and ameliorating punch die. At last, a better method was chosen to promote a complete set of industrial technique of production of AuSn20 solder foil and ring.