Research On Manufacture And Applications Of Ausn20 Solder Preform

With the development of electronic and opto-electronic industries, eutectic AuSn20 solder is applied in many fields more and more frequently, also, many studies are focused on this solder all over the world. It is all because of its excellent properties of strength, thermal conductivity, heat fatigue & crack growth resistance, wettabillity and spreadability. Furthermore, this solder can suit fluxless process. All of these merits make it a perfect choice of solder material for electronic and opto-electronic packagings. Though, the high brittleness of this solder causes it hard to process, this shortage limits the development of this solder.In this paper, a new method, casting-toughening-blanking method, to manufacture AuSn20 solder preform is introduced; solder preform is a common form of AuSn20 solder. In this method, AuSn20 alloy sheet is produced firstly. Then the sheet goes through a hot-processing at 260℃for an hour to make it tough enough to mechanical process. After this process, the hardness of the sheet can reduce from 180HV to 125.3HV. Finally, the sheet is blanked to the shapes needed. The samples of this method have precise component, flawless shape and outstanding solderablity.Then manufacture facilities based this method are designed. Masses of samples with various shapes are produced. These samples are tested in two practical applications, optical fiber soldering and MEMS hermetic packaging. The results exhibit the samples'strong wettabillty, and the joints are smooth without any void, which make it better is that the joints have super air-tightness. After certification, the experts believe the products have excellent properties up to the international advanced level, can substitute expensive AuSn20 solder preform imported without any difference.