| dc.description.abstract | With advancements in advanced electronic packaging technologies, the inclusion of various materials with different properties in multilayer stack structures poses challenges such as chip warpage and long-term reliability issues when subjected to high-temperature processes. Sn-58Bi solder, with a melting point of 138°C, exhibits excellent resistance to creep deformation. Wetting property is crucial during reflow, thus in this experiment, both halogen-containing and halogen-free Sn-Bi solder, as well as halogen-free Sn-56Bi1Ag0.2C solder, were selected to investigate their wetting characteristics on copper substrates at different reflow temperatures and times.
From the TG-DTA results, it was observed that the addition of halogens had no impact on the solder′s melting point. The addition of copper-silver to the solder resulted in a one-degree decrease in the melting point. For the halogen-containing SnBi solder, the contact angle was consistently above 18 degrees. This indicates that temperature had minimal effect on the wetting property . On the other hand, the halogen-free solder exhibited lower contact angles compared to the halogen-containing solder, indicating better wetting characteristics. The thermal analysis results showed that the halogen-containing solder had a rapidly weight loss rate after reaching the melting point. This suggests that the flux in the halogen-containing solder evaporated rapidly during the reflow process, possibly leading to insufficient protection of the solder and substrate from oxidation, resulting in a decrease in wetting property. The addition of silver and copper to the SnBi solder improved wetting characteristics, as silver possesses excellent antioxidation properties, leading to better wetting properties. | en_US |