Effects of Ga alloying on microstructure and comprehensive performances of Sn–9Zn–2Bi alloys for the microelectronics industry. (August 2022)

• Record Type: Journal Article
• Authors: Peng, Yanzhi; Li, Caiju; Xiao, Kunxuan; Yang, Jiaojiao; Pu, Cunji; Gao, Peng; Guo, Shaoxiong; Zhang, Jiatao; Yi, Jianhong
• Is Part Of: Microelectronics and reliability. Volume 135(2022)
• Publication Date: 2022-08
• Subjects: Sn–Zn–Bi–Ga alloy -- Solder -- Microstructure -- Corrosion resistance -- Thermal behavior; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2022.114599
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: In this work, we developed Ga-doped Sn-based solders for the microelectronics industry. The microstructures, melting properties, wetting performance, electrical conductivities, electrochemical corrosion behaviors, and mechanical properties of the Sn–9Zn–2Bi–xGa (x = 0.05, 0.1, 0.3 and 0.5 wt%) alloys were investigated. The results indicated that Ga addition led to the disappearance of the coarse Zn-rich phase. Ga was found solubilized in the Zn phase, without the formation of intermetallic compound (IMC). Ga reduced the fusion point of the Sn–9Zn–2Bi alloy, while the pasty and undercooling range increased. Ga addition was found beneficial to the wettability of the Sn–9Zn–2Bi alloy, but increased the resistivity slightly. The ultimate tensile strength of the Ga-containing alloys was improved. The fracture was diverted from the near–completely ductile fracture to the mixed rupture feature. When Ga concentration was 0.3 wt%, the corrosion product layer of the Sn–Zn–Bi–Ga alloy was uniform and dense, which effectively prevented the alloy from further corrosion. Graphical abstract: Unlabelled Image Highlights: The additions of Ga refined the microstructure, resulting in smaller Zn–rich phase. The addition of Ga decreases the melting temperature and increases the ultimate tensile strength. Adding a small amount of Ga substantially improves the wetting performance of Sn-9Zn-2Bi alloy. Sn-9Zn-2Bi-xGa alloys exhibit reasonable electrical properties. The corrosion resistance of Sn–9Zn–2Bi solder alloys is improved by Ga element additions.