An ion beam layer removal method of determining the residual stress in the as-fabricated TSV-Cu/TiW/SiO2/Si interface on a nanoscale
An ion beam layer removal method of determining the residual stress in the as-fabricated TSV-Cu/TiW/SiO2/Si interface on a nanoscale
复制标题
一种确定纳米级 TSV-Cu/TiW/SiO2/Si 界面残余应力的离子束层去除方法
DOI：
10.1016/j.microrel.2020.113826
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发表时间：
2020-09-01
影响因子：
1.6
通讯作者：
Huang, Y.
中科院分区：
文献类型：
--
作者：
Chen, S.;En, Y. F.;Huang, Y.
硅通孔（TSV）中TSV-Cu/TiW/SiO2/Si界面上的热致残余应力引起了人们对3D IC机械和电气可靠性的严重关注。由于缺乏纳米级的TSV界面应力梯度测量技术，使得TSV界面失效机理不清楚。在这项工作中，我们提出了一种离子束层去除（ILR）的方法，用于确定残余应力在所制造的TSV-Cu/TiW/SiO2/Si界面上的纳米尺度，以便于识别的TSV-Cu/TiW/SiO2/Si界面的故障机制在所制造的TSV。测量结果表明，TSV-Cu/TiW/SiO2/Si界面上的残余应力存在波动，界面系统中既存在压应力，又存在拉应力。压应力发生在所有三个界面，TSV-Cu/TiW，TiW/SiO2和SiO2/Si界面，但在距离这些界面25-45 nm处转变为张应力。最高水平的剪切应力集中出现在TSV-Cu内部，距离TSV-Cu/TiW界面约45 nm。这种剪切应力集中解释了实验观察到的TSV界面开裂现象。
Thermally induced residual stresses across the TSV-Cu/TiW/SiO2/Si interface in through-silicon vias (TSVs) have raised serious concerns about mechanical and electrical reliability in 3D ICs. The lack of a nanometer-precision measurement technique for the TSV interfacial stress gradient makes the interface failure mechanism unclear. In this work, we propose an ion beam layer removal (ILR) method for determining the residual stress in the as-fabricated TSV-Cu/TiW/SiO2/Si interface on a nanoscale to facilitate identification of the failure mechanism of the TSV-Cu/TiW/SiO2/Si interface in as-fabricated TSVs. The measurement results showed that the residual stress fluctuates across the TSV-Cu/TiW/SiO2/Si interface and that both compressive stress and tensile stress existed within the interface system. Compressive stress occurred at all three interfaces, the TSV-Cu/TiW, TiW/SiO2, and SiO2/Si interfaces, but transitioned to tensile stress at a distance of 25-45 nm from these interfaces. The highest level of shear stress concentration appeared inside the TSV-Cu at a distance of approximately 45 nm from the TSV-Cu/TiW interface. This shear stress concentration explains the experimentally observed TSV interfacial cracking phenomenon.