Yuan Xiaohong, He Qinlian, Wang Xiaojing, Zhang Jiaheng, Yang Dapeng, Bi Qinsong, Luo Yuxi, Chen Dengquan, Zheng Shanju, Ebaid Manal S, Algadi Hassan, Guo Zhanhu
Yunnan Precious Metals Lab, Sino-Platinum Metals Co. Ltd., Kunming 650106, China.
State Key Laboratory of Precious Metal Functional Materials, Kunming 650106, China.
ACS Appl Mater Interfaces. 2025 Jun 25;17(25):37193-37205. doi: 10.1021/acsami.5c03751. Epub 2025 Jun 13.
Continuously improving chip integration and increasing packaging density increase the risk of performance degradation and electromigration (EM) failure on the bonding interface during electrical transmission. While EM failure, as a time-accumulated failure, is one core challenge of semiconductor reliability and is particularly severe in highly integrated chips. However, the polarity differences existing in commercial devices and the evolving polarity characteristics of microscale bonding interfaces have not been well addressed. Therefore, this study describes the polarity effects of EM in a commercial chip-end Au-Al system and reveals the evolution of intermetallic compound (IMC) growth at bonding interfaces under high-density currents. An EM simulation model is developed to jointly analyze the influence of current-induced polarity effects on the evolution of material migration and IMC growth together with experimental results. Specifically, under the influence of the polarity effect, the thickness of the anode IMC layer is approximately twice as thick as that of the cathode. The IMC thickness on both sides is much thicker than the center under the influence of the size effect. Unlike previous studies, the IMC at the commercial bonding interface is mainly the AlAu phase in columnar crystal morphology and the α-AlAu phase in nanocrystalline morphology, with the former being mainly located in the middle region of the IMC layer, while the latter is mainly located in the edge region of the IMC layer. Due to the overgrowth of the IMC layer, the tensile mechanical properties of the interface are degraded, and the failure mode transforms from a single neck fracture to a predominant joint detachment. This study complements and improves the research framework of Au/Al interface IMC at commercial chip joints and lays a theoretical foundation for the development of semiconductor chips toward high integration, high density, and high reliability.
不断提高的芯片集成度和不断增加的封装密度，增加了电传输过程中键合界面性能退化和电迁移（EM）失效的风险。虽然EM失效作为一种随时间累积的失效，是半导体可靠性的核心挑战之一，在高度集成的芯片中尤为严重。然而，商业器件中存在的极性差异以及微观键合界面不断演变的极性特性尚未得到很好的解决。因此，本研究描述了商业芯片端金铝系统中EM的极性效应，并揭示了高密度电流下键合界面金属间化合物（IMC）生长的演变。开发了一个EM模拟模型，将电流诱导的极性效应对材料迁移演变和IMC生长的影响与实验结果联合起来进行分析。具体而言，在极性效应的影响下，阳极IMC层的厚度约为阴极的两倍。在尺寸效应的影响下，两侧的IMC厚度比中心厚得多。与以往的研究不同，商业键合界面处的IMC主要是柱状晶形态的AlAu相和纳米晶形态的α-AlAu相，前者主要位于IMC层的中间区域，而后者主要位于IMC层的边缘区域。由于IMC层的过度生长，界面的拉伸力学性能退化，失效模式从单一的颈部断裂转变为主要的接头脱离。本研究补充并完善了商业芯片接头处金/铝界面IMC的研究框架，为半导体芯片向高集成、高密度和高可靠性发展奠定了理论基础。
