Effect of Interfacial Reaction in Sn-Ag-Cu Solder Alloy with Ni Addition

Abstract

Sn-Ag-Cu-Ni-Ge solder alloy has been developed to improve the mechanical properties of the Sn-Ag-Cu base solders and prevent oxidation of those solders. In this paper, an interfacial reaction and microstructure between the solder and a Cu electrode were investigated under heat exposure conditions. It was found that intermetallic compounds growth at the interface of the solder and the Cu electrode was greatly affected by amounts of added elements. Adding Ni in the solder can suppress the formation and growth of intermetallic compounds (IMCs) such as Cu-Sn and decreasing the amount of adding Ag in the solder can prevent the formation and growth of Ag3Sn. Moreover, it was found that there was an effect of suppress the growth of the Cu3Sn formed on the interface of Cu and (Cu,Ni)6Sn5 by adding Ni from analysis results of EDX and TEM.

Impact properties of Sn-3Ag-0.5Cu solder ball joint with epoxy-based flux

“…After aging at 120℃ for 6 weeks, the reaction layer which is composed of two Cu-Sn compounds layers was observed regardless of flux type. These layers seem to be Cu 6 Sn 5 and Cu 3 Sn [6]. The Cu 6 Sn 5 and Cu 3 Sn layers form on the solder side and the Cu side, respectively.…”

“…On the contrary, solder fracture increased upon aging and thus it was the major fracture mode in the joint with epoxy-based flux. On the basis of EPMA mapping analysis of fracture surfaces, it was clarified that IMC fracture corresponds to fracture at the solder/ (Cu,Ni) 6 not sufficient, IMC does not form uniformly at the joint interface. In such joint, fracture easily occurs at the joint interface.…”

Divide and conquer： Machine learning accelerated design of lead-free solder alloys with high strength and high ductility

“…Alloying Al element refines the β-Sn phase particles in SAC105 solder, inhibits the formation of Ag3Sn and Cu6Sn5 IMCs, and forms new Ag3Al and Al2Cu IMCs, thereby significantly increasing the strength and decreasing the ductility [43] . Alloying Ni atoms generate a more dense and stable (Cu, Ni)6Sn5 IMC interface layer between solder and Cu-based substrate, which becomes a barrier layer against the growth of brittle Cu3Sn IMC and hence improves the drop resistance [44] . However, big size IMCs are usually very brittle, meaning strengthening by the precipitation mechanism might impair the ductility when IMCs are big in size.…”

Intermetallic Study on the Modified Sn-3.5Ag-1.0Cu-1.0Zn Lead Free Solder

“…Although the Sn-Ag-Cu solders are accepted widely but there still some room for improvements. Many researchers studied the addition of minor elements such as Ni, Zn, Co, Sb and Bi that can improve the properties of Sn-Ag-Cu solders [2][3][4].…”