Improving the impact toughness of Sn–Ag–Cu/Cu–Zn Pb-free solder joints under high speed shear testing
2013; Elsevier BV; Volume: 586; Linguagem: Inglês
10.1016/j.jallcom.2013.10.113
ISSN1873-4669
AutoresChi-Yang Yu, Wei-Yu Chen, Jenq‐Gong Duh,
Tópico(s)3D IC and TSV technologies
ResumoThis study aims to investigate the interfacial reaction and the impact reliability of Sn–3.0Ag–0.5Cu/Cu–15Zn (wt.%; SAC/Cu–Zn) solder joints. The Cu–Zn under bump metallization (UBM) was developed to replace the traditional Cu UBM in the Pb-free solder joints. In the Sn–Ag–Cu/Cu solder joint, thick Cu6Sn5 and Cu3Sn intermetallic compounds (IMCs) formed at the interface after thermal aging at 150 °C for 1000 h. In contrast, the SAC/Cu–Zn solder joint shows a thinner Cu6(Sn,Zn)5 layer, and the growth of Cu3Sn IMC was absolutely suppressed at the SAC/Cu–Zn interface. To evaluate the bonding energy, the high speed shear testing was carried out to correlate the microstructure of solder joints. It is noteworthy that the SAC/Cu–Zn solder joint can enhance the impact toughness. The higher impact toughness of SAC/Cu–Zn is attributed to the thinner and tougher Cu6(Sn,Zn)5 IMC at the joint interface. Accordingly, Cu–Zn alloy is a potential UBM material for Pb-free solder joints to improve the impact reliability.
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