Scholarlink

<p>Bismuth is added to Sn–Ag–Cu-based solders to increase strength and solder joint reliability but accelerated thermal cycling (ATC) tests have shown variable thermal fatigue performance. To better understand their thermal fatigue mechanisms, we investigate three Sn–Ag–Cu-Bi solder alloys containing between 3 and 6 wt.% bismuth in two types of ball grid array (BGA) packages tested using a harsh ATC profile of -55/125&#xa0;°C. We study how the bismuth additions affect the microstructure after soldering, after ~ 4&#xa0;years storage at room temperature and after thermal cycling. The Weibull reliability statistics are then correlated with the microstructural evolution including solutionising, homogenisation, bismuth precipitation, recrystallisation and crack paths. The results show that high strength Sn–Ag–Cu-Bi solders can improve the resistance to thermal fatigue, but high solder strength needs to be balanced against excessive stress transfer to the intermetallic attachment layer.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effects of bismuth on the microstructure and crack propagation in Sn–Ag–Cu-Bi solder joints during thermal cycling

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年10月24日

查看全文
  • C. L. Hsieh,
  • R. J. Coyle,
  • S. A. Belyakov,
  • J. W. Xian,
  • C. M. Gourlay

摘要

Bismuth is added to Sn–Ag–Cu-based solders to increase strength and solder joint reliability but accelerated thermal cycling (ATC) tests have shown variable thermal fatigue performance. To better understand their thermal fatigue mechanisms, we investigate three Sn–Ag–Cu-Bi solder alloys containing between 3 and 6 wt.% bismuth in two types of ball grid array (BGA) packages tested using a harsh ATC profile of -55/125 °C. We study how the bismuth additions affect the microstructure after soldering, after ~ 4 years storage at room temperature and after thermal cycling. The Weibull reliability statistics are then correlated with the microstructural evolution including solutionising, homogenisation, bismuth precipitation, recrystallisation and crack paths. The results show that high strength Sn–Ag–Cu-Bi solders can improve the resistance to thermal fatigue, but high solder strength needs to be balanced against excessive stress transfer to the intermetallic attachment layer.