ELECTRODEPOSITION, GROWTH-MORPHOLOGY AND MELTING CHARACTERISTICS OF GOLD-TIN EUTECTIC ALLOYS

Eutectic Au-Sn (80/20 percent by weight) solders have good electrical and heat conducting properties, as mel as superior thermal fatigue str ength as compared to other material used in microelectronics assembly, such as SnPb-solders and conducting epoxies. A chemistry has been dev eloped to electroplate high quality Au-Sn deposits and to characterize the coatings in terms of alloy and phase composition, structure, and melting characteristics. An operatively window and the long-term stabi lity of the plating process have been established.