Abstract Copper (Cu)-filled through silicon (Si) via (CF-TSV) acts as an electrical conduit between different layers of circuitry in the advanced microelectronic devices. Due to wide difference in the coefficient of thermal expansion between Cu and Si, large thermal stresses get generated in both Si and Cu during the inevitable thermal excursions taking place during fabrication of microelectronic devices and their regular operation. This study examines the fracture of Si wafer in a CF-TSV due to annealing over the temperature range of 250–550 °C and the post-annealing natural ageing. Nucleation of micro-cracks in Si in the vicinity of the Cu pillars were observed, which propagated at a constant velocity during post-annealing room temperature ageing, thereby substantiating delayed fracture in Si. Microstructural examination revealed that the micro-cracks nucleated as a result of formation of a Cu-Si compound during annealing, whereas the crack propagated due to the oxidation of Si at the crack tip. Consistently, the micro-cracks did not propagate when the sample was stored in high vacuum. Furthermore, Raman spectroscopy and finite element method were used to gain insights into stress generation due to Cu-Si reaction, and nucleation and propagation of the crack.

中文翻译：

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热退火期间和之后填充铜的硅通孔中的 Si 断裂的新见解

摘要 铜 (Cu) 填充硅 (Si) 通孔 (CF-TSV) 在先进微电子器件中充当不同电路层之间的电气管道。由于 Cu 和 Si 之间的热膨胀系数差异很大，在微电子器件制造及其正常运行过程中不可避免地发生热偏移期间，Si 和 Cu 中都会产生很大的热应力。本研究检查了 CF-TSV 中 Si 晶片由于在 250-550 °C 的温度范围内退火和退火后的自然时效而导致的断裂。观察到 Cu 柱附近 Si 中微裂纹的形核，其在后退火室温时效期间以恒定速度传播，从而证实了 Si 中的延迟断裂。显微组织检查表明，微裂纹是在退火过程中形成的 Cu-Si 化合物的结果，而裂纹由于裂纹尖端的 ​​Si 氧化而扩展。一致地，当样品储存在高真空中时，微裂纹不会扩展。此外，拉曼光谱和有限元方法被用来深入了解由于铜硅反应产生的应力，以及裂纹的成核和扩展。