LEAD FREE SOLDER ALLOY AND MANUFACTURING METHOD THEREOF

摘要

A lead-free solder alloy and a method for manufacturing the lead-free solder alloy using a high frequency vacuum induction furnace are provided, wherein the lead-free solder alloy improves mechanical strength, thermal strength and accelerated impact performance of the alloy by having a fusion point similar to that of a conventional lead-free solder alloy, a very low segregation ratio, and excellent wettability and bonding characteristics with a base metal to be bonded. As a lead-free solder alloy used in a printed circuit board treated with nickel(Ni)/gold(Au), the lead-free solder alloy comprises 0.8 to 1.2 wt.% of silver(Ag), 0.8 to 1.2 wt.% of copper(Cu), 0.01 to 1.0 wt.% of palladium(Pd), 0.001 to 0.1 wt.% of tellurium(Te), and the balance of tin(Sn), wherein intermetallic compounds with compositions of (Cu, Ni)6Sn5 and Cu6Sn5 are formed by Cu and Sn of the lead-free solder alloy and Ni of the printed circuit board, and wherein acicular structure of the intermetallic compounds is further densified and formed in a chain shape by bonding the palladium(Pd) and copper(Cu), and the palladium(Pd) and tin(Sn) respectively on an interface of the intermetallic compounds, thereby forming a Cu3Pd compound and a PdSn4 compound.