COMPOSITE FOR LEAD-FREE SOLDER SN-AG-CU-IN-BI ALLOY HAVING LOW MELTING POINT

摘要

PURPOSE: Quinary low melting point lead free solder is provided to minimize physical damage in case of bonding an electronic substrate by being environment-friendly and having excellent physical property simultaneous with a low melting point. CONSTITUTION: Quinary low melting point lead free solder includes tin(Sn), silver(Ag), copper(Cu), indium(In) and bismuth(Bi). The lead free solder composition comprises 85-99 weight% tin, 0.8-1.2 weight% silver, 0.1-1.0 weight% copper, 0.1-1.0 weight% indium and 5-10 weight% bismuth by weight based on the total weight of the composition. The lead free solder composition further includes at least more than one selected element of nickel(Ni), zinc(Zn), antimony(Sb), gallium(Ga) and phosphorous(P) by weight based on the total weight of the composition. The lead free solder composition possibly selectively further includes more than one metal selected from nickel, antimony and gallium to intensify the mechanical property although the mechanical property is excellent. The lead free solder manufactured with the lead free solder composition possibly is a form of alloy. Using an example usage of the lead free solder composition such as wave soldering, electrodeposition or soldering paste, integrated circuit chips are electrically connected to a circuitized substrate.