【作者】 尚帅华；

【导师】 杨平；

【作者基本信息】 江苏大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 随着社会经济、科学技术的发展与进步,人们对信息量的需求越来越大,信息的大容量存储和高速度传输问题迫在眉睫。这势必要求电子元器件及系统设备快速升级,即朝着轻、薄、短、小、低功耗、多功能、高可靠性方向发展,正如超大规模集成电路的出现。这预示着更多的金属薄膜及多层膜材料应用于微电子元器件中。如Al-Cr薄膜材料用于a-Si TFT的双层电极及极紫外波段滤光片;W-Al材料用于薄膜体声波谐振器(FBAR)布拉格反射层,元件间连线,扩散障碍层等。由于膜-基体系微构造的机械特性是薄膜质量的首要指标和发挥其性能的基本条件,在很大程度上决定了薄膜及器件的可靠性和使用寿命。因此,研究双层金属薄膜界面构造机械特性是很有必要的。本文采用磁控溅射法制备了过渡金属Cr、W材料与Al配对的双层薄膜样品Al-Cr、W-Al和Al-W,研究内容分别如下:1.测试双层金属薄膜材料在微尺度下的机械性能。在样品Al-Cr和W-Al表面上选择合适的压痕位置,利用纳米压痕仪对多个点进行不同深度的测试,获得Al、W薄膜的弹性模量、硬度及随着压痕深度变化的关系曲线。2.建立有限元模型并仿真计算。利用ANSYS软件建立压头对样品加卸载接触过程的轴对称模型,并施加位移函数进行计算。得到样品Al-Cr和W-Al的载荷-位移曲线,与实验数据对比;对样品W-Al模型中应力应变的分布进行研究,得到其分布云图。3.施加热载荷。采用高低温综合试验箱对样品W-Al和Al-W施加热载荷,温度范围为-40-120℃,循环周期为120分钟,在最值温度处均保持恒温15分钟,共加载5个周期。4.测试样品的界面结合强度。采用纳米划痕仪分别测试经过热循环和未经过热循环的样品W-Al和Al-W的界面结合力,并对比分析,发现热循环载荷对界面结合强度有增强作用。通过对划擦痕迹的观测,进一步验证了划痕实验中界面结构破坏的一般过程。综上所述,本文采用了实验测试结合有限元仿真的方法分析了双层金属薄膜样品的机械力学特性,分析的结果可以有效的促进薄膜界面结构力学及物理机制方面的研究,同时也对微电子元件界面结构的优化设计、工程应用以及技术推广有一定的积极作用。更多还原

【Abstract】 With the development of social economy and technology, people’ demand for information has been being more and more, so the problem of large-capacity storage and high-speed transmission of information seems imminent. This will inevitably require that the devices, like electronic components and systems, should upgrade quickly, that is to say, the development should be toward to the direction for light, thin, short, small, low power, multi-function, high reliability, like the appearance of very large scale integrated circuit. This indicates that the metal thin film and multilayer materials will be applied more widely to microelectronic components. For instance, the Al-Cr thin-film material is used as a two-layer electrode structure in a-Si TFT and used to prepare extreme ultraviolet filter, and W-Al thin-film material is used as the Bragg reflection layer in thin-film bulk acoustic resonator (FBAR), interconnect components and diffusion barrier layer. And the micro-structure mechanical characteristics of film material are the primary index and basic performance of film quality, to some great extent, determining the reliability and life of films and devices. Therefore, the work of studying the interfacial structure mechanical properties of double-layer metal film is very necessary.In this paper, the double-layer thin film paired samples of Al-Cr, W-Al and W-Al were prepared by using the method of magnetron sputtering and the materials of Al and transition metals Cr, W. And the author investigated the mechanical properties of samples from the following aspects.1. Test mechanical properties of double-layer metal film material under the micro-scale. The author chose appropriate positions for indentation on the samples’ surface of Al-Cr and W-Al, and tested multiple points with different depths by using nano-indentation instrument. As a result, the elastic modulus, hardness and the relationship curves with depth changes have been obtained.2. Establish finite element model and simulate. The loading and unloading processes of the indent contacting samples were simplified as axisymmetric model, the displacement function and calculation were conducted by using the software ANSYS. The load-displacement curves were obtained, and were compared with experimental data, but also the distributions of stress and strain in the W-Al model have been investigated.3. Apply thermal load. The High-low temperature test box was used to apply thermal load to sample W-Al and Al-W, with a range of -40-120℃, a cycle of 120 minutes and total five loading cycles. And the temperature at the most values retained constant for 15 minutes.4. Test interfacial bonding strength of samples. The Nano-Scratch Tester was used to respectively measure the interfacial bonding strength of the samples W-Al and Al-W that were conducted thermal cycling and without. And after comparing the two values, the result shows that thermal cycling load could enhance the interfacial strength. And the scratch traces of the samples were observed to prove the general process of interfacial structure damage.In summary, the paper uses the method of combining test with finite element simulation to analyze the mechanical properties of the double layer metal film samples. The analytical results can effectively promote the developments of the interface structural mechanics and physical mechanism research, and may also play a certain positive role on the interfacial structure optimization design of micro-electronic devices, engineering application and technology popularization.更多还原