计量型原子力显微镜的研究

【作者】 高思田；

【导师】 胡小唐；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2007， 博士

【摘要】 原子力显微镜是纳米科技的重要测量手段,本课题围绕原子力显微镜的计量化进行了系统的研究和分析,包括计量型原子力显微镜的建立、主要误差来源分析、计量型原子力显微镜的校准以及纳米标准样板的制造和测量分析。主要工作有:1.对原子力显微镜的测量模式、微悬臂位置检测方式、扫描器和计量系统进行了分析研究,指出了计量型原子力显微镜需要:1)采用柔性铰链+压电陶瓷组成的纳米位移台;2)具有三维激光干涉测量系统。2.研制了计量型原子力显微镜。对共焦传感器微悬臂位置系统、三维柔性铰链位移系统的结构进行了理论分析和实验测试。实现了无阿贝误差的三维激光干涉测量系统。采用分布控制方式的控制系统,提高了系统的测量速度。提出了一种新的x向扫描方式-x方向自适应变速扫描方式,根据表面结构的实时状况采用不同的扫描速度,可大大降低对z向位移的频率响应的要求,且又能保证较高的测量速度。3.分析了环境因素中温度、湿度、振动对原子力显微镜测量的影响,特别指出了在纳米测量中,温度导致的尺寸变化主要体现在仪器上而不是被测样品上。对针尖几何形状导致的测量误差进行了分析研究,阐述了几种表面重建方法,给出了相应的计算公式。4.对位置误差的校准与补偿进行系统的分析和研究,建立了扫描器的运动模型,首次提出了全空间校准的概念,并采用了单轴校准和全空间校准组合式的方案,完善了原子力显微镜的校准方法。提出并实现了微悬臂的校准方法,保证了从计量型原子力显微镜得到所有数据均可溯源到激光波长。5.研制了台阶高度和线宽两种纳米几何结构样板,与德国物理技术研究院(PTB)、中国科学院微电子中心和无锡华晶集团进行了比对测量。通过台阶高度和两维线间隔的国际比对,提出了两种样板的标准算法,首次对不确定度进行分析评定,建立标准的评定方法。6.计量型原子力显微镜于2007年4月通过了国家技术监督检验检疫总局组织的专家考核,即将成为正式的国家最高计量标准,用于我国台阶高度和线间隔两个参数的量值传递。更多还原

【Abstract】 Atomic Force Microscope (AFM) is one of most important tools in nanotechnology. This thesis is concentrated on the theoretical and experimental researches on metrological AFM, which include the building of metrological atomic force microscope, the analysis of error sources, the calibration of metrological atomic force microscope, and the manufacture and measurement of nano geometric references. The main work of the thesis includes the follows.1. The measuring mode, measuring method of the cantilever position, scanner and the metrological system are theoretically analyzed. It is pointed out that a metrological atomic force microscope should 1) use the scanner consisting of flexure hinges and piezo stacks; 2) have three dimensional laser interferometer system.2. A metrological atomic force microscope has been developed. A confocal sensor for positioning the cantilever, a scanner with three dimensional monolithic flexure hinges have been theoretically and experimentally analyzed. An Abbe-error free three dimensional laser interferometer has been realized. Because of using the distributed control system, the measuring speed has been improved. A new scanning method for the x direction has been proposed, which can be called self-adaptive speed scanning method and can use different scanning speeds according to the surface topography. The new method reduces the requirement for the frequency response in z direction greatly and ensures relative high measuring speed in the mean time.3. The influences of environment, such as temperature, humidity, vibration etc, have been analyzed. It is especially pointed out that the variation of temperature influences the instrument rather than the artifacts. The measuring error coming from geometric shape of the tip has been analyzed. The surface reconstruction methods have been expatiated and the calculation formulas have been given.4. The calibration and compensation of positioning errors have been fully analyzed and studied. The moving mode of the scanner has been built. A new concept - total space calibration has been proposed. Both the single axis calibration and the total space calibration have been used in the metrological atomic force microscope, and work quite well. The calibration method for the cantilever has been proposed and realized. Thus all the data obtained from metrological atomic force microscope can be traced to the laser wavelength.5. Sets of step height references and line width references have been developed. The comparison measurements have been carried out among Physikalish Technishche Bundesanstalt (PTB), Germany, National Institute of Metrology (NIM), China, Microelectronic Center of Chinese Academy of Science and Huajing Microelectronic Co. The metrological atomic force microscope has been used for the international comparison of step height references and two dimensional gratings. The standard calculation methods and the standard measurement uncertainty evaluation procedures have been proposed for above two types of artifacts.6. The metrological atomic force microscope has been assessed by the experts from the State General Administration for Quality Supervision and Inspection and Quarantine, China, and will work as the highest national metrological reference instrument for the calibration of step heights and pitches.更多还原