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提出了一种基于扩散-蠕变机制的空洞生长模型,结合应力模拟计算和聚焦离子束分析技术研究了Cu互连应力诱生空洞失效现象,探讨了应力诱生空洞的形成机制并分析了空洞生长速率与温度、应力梯度和扩散路径的关系.研究结果表明,在CuM1互连顶端通孔拐角底部处应力和应力梯度达到极大值并观察到空洞出现.应力梯度是决定空洞成核位置及空洞生长速率的关键因素.应力迁移是空位在应力梯度作用下沿主导扩散路径进行的空位积聚与成核现象,应力梯度的作用与扩散作用随温度变化方向相反,并存在一个中值温度使得应力诱生空洞速率达到极大值.
A cavity growth model based on diffusion-creep mechanism is proposed. The stress-induced cavitation failure in Cu interconnection is studied by stress simulation and focused ion beam analysis. The formation mechanism of stress induced cavities is discussed. The relationship between growth rate, temperature, stress gradient and diffusion path.The results show that the stress and the stress gradient reach the maximum at the bottom of the corner of the top CuM1 interconnection and the occurrence of cavities is observed.The stress gradient is the key point for determining the nucleation and The key factor of void growth rate is stress migration, which is the vacancy accumulation and nucleation along the dominant diffusion path under the action of stress gradient. The effect of stress gradient and diffusion are opposite to the change of temperature, and there is a medium temperature so that the stress Induced voids rate reached a maximum.