The formation of intermetallic compounds (IMCs) at solder/substrate interfaces is essential, which have a critical effect on the mechanical reliability of solder joints. In this study, nanoindentation was used to investigate elastic modulus, hardness and creep properties of the IMCs formed at the interface between Sn-Cu (-Ni) solder ball grid arrays (BGAs) and Cu substrates in multiple-reflowed samples. All the tests were conducted at room temperature. The elastic modulus and hardness of (Cu,Ni)6Sn 5 were higher than those of Cu6Sn5. The hardnesses of (Cu,Ni)6Sn5 were scattered, which may be attributed to the crystallographic characteristics such as a growth texture of the IMCs. The creep stress exponents of the IMCs were extremely high (9.5∼44), compared to pure tin and solder alloys.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering