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题名	纳米级多功能聚焦离子束光柱体的研究; 纳米级多功能聚焦离子束光柱体的研究
作者	1李文萍,电工研究所
学位类别	博士
答辩日期	2007-01-10
授予单位	中国科学院电工研究所
导师	1顾文琪,电工研究所
关键词	聚集离子束 动态校正 三维模型法 一体化设计 库仑力效应 Focused ion beam, Dynamic correction, 3-D modeling, Integrated design
其他题名	纳米级多功能聚焦离子束光柱体的研究
中文摘要	聚焦离子束(Focused ion beam－FIB）技术兼具分辨率高和多功能的特点， 适应了半导体产品微型化对微细加工提出的新要求，逐渐成为微电子领域必不可少的关键加工技术之一。聚焦离子束技术的发展和应用的扩展对FIB装置提出了更高的要求：既能在大束流加工时稳定的工作，又能在小束流下获得细束斑用于纳米领域。目前FIB装置种类繁多，但都是针对某一类功能而设计，很少在一套设备内实现聚焦离子束的各项功能。多功能纳米级离子光柱体的研制将为半导体微电子科学研究、纳米科技和MEMS研究提供多功能、多用途的纳米加工装置。离子束光柱体包括聚焦系统、偏转扫描系统、对中调整系统以及扩展功能的质量分析器等。针对多功能纳米级离子光柱体对各个部分的性能要求，本论文首先分别对透镜系统、偏转器、对中调整系统以及质量分析器进行了优化设计，然后将各个光学器件组合起来进行一体化设计。在离子光学理论方面计算了离子间的库仑力效应，并首次将自动微分方法扩展到离子光学实际场的设计计算中。 透镜系统的设计中，提出用阻尼最小二乘法计算单个透镜和透镜系统。首先采用先分解再组合的方法确定单个透镜参数，并以大束流、无限大放大倍数下像差系数与焦距的比为优化的目标。然后在不同束流和能量下优化两级透镜系统，实现了一套系统内同时具有刻蚀、沉积、离子成像和注入等功能。偏转扫描系统采用透镜前双静电偏转器，通过调整上下两个偏转器的长度和电极电压比例，有效减小了偏转场的色差。设计中充分利用电信号叠加的优势，通过在两个偏转器和第二透镜上加上适当的动态校正信号实现对偏转畸变、像散和场曲的动态校正，降低了光学系统的复杂度。对中和消像散器的设计中借鉴了偏转场设计中的叠加原理，可以实现对离子光柱体加工和装配误差的校正。提出用三维模型法设计 质量分析器，根据永久磁铁的磁场解析表达式进行优化，设计出相对均匀的电磁场，分析器两端的屏蔽铁环有效减小了边缘效应，设计的质量分析器分辨率为0.07。各个光学器件设计完成后，将它们组合起来采用五阶龙格－库塔法直接轨迹追踪，实现了离子束光柱体的一体化设计，并利用蒙特卡罗方法仿真了离子间的库仑力效应。 论文的最后研究了聚焦离子束光柱体和扫描电镜联机的一些关键技术，结合目前聚焦离子束装置的应用现状指出了聚焦离子束技术光柱体的发展方向。 With high resolution and flexible applications, focused ion beam (FIB) system becomes an important tool in micro-fabrication industry. The development of FIB technology requires that FIB devices not only can work well in bigger currents but also have better performance in nanometer scale. There are many kinds of FIB devices in the present, but few of them can achieve all the applications of focused ion beam. Research on multipurpose ion optical column in nanometer scale will provide multifunctional nanometer device for semiconductor microelectronic industry, nanotechnology and MEMS technology. Focused ion optical column includes focusing system, deflection system, aligning system and mass separator. In this paper we first designed separator module of ion column according to its own behavior, then optimized the ion column by integrating them together as a whole. On the side of ion optics theory, the coulomb effect among ions was calculated and automatic differentiation technique was expanded into designing practical optical column in this paper. Damped least square method was brought forward to design single lens and the lenses system. Single lens is designed through combination of separating and assembling, and the optimized objective is chosen as the ratio of aberration coefficient and focus length at infinite magnification. To realize etching, deposition, implantation and imaging in the same system, the lenses system has been designed by optimizing its optical properties in different beam currents and different beam energies. Two pre-lens deflectors can effectively reduce the deflecting chromatic aberration by adjusting the length and potential ratio of the two deflectors. Deflection distortion, astigmatism and field curvature can be dynamically corrected by applying suitable signal on both deflectors and lens 2, which will reduce the complexity of optical column considering the superposition of electric signals. Referring to the superposition principle in design deflectors, beam aligner and stigmator can correct the error introduced by machining and assembling. Based on the analytic expression of magnetic field distribution, a new 3D model is built and optimized to obtain a homogenous field with negligible fringing effect. The mass resolution of our designed separator is 0.07. After we have designed the lenses system, deflectors, beam aligner, stigmator and mass separator, integrated design of ion optical column was realized by using fifth order Runge-Kutta trace the ions directly. We also simulated the coulomb effect among ions through Monte Carlo method. An example of integrating focused ion beam column in a SEM system is given to research the extensibility of FIB optical column. The trend of development in FIB optical column is summarized at the end of this paper.
语种	中文
公开日期	2010-10-18
页码	152
分类号	TM1
内容类型	学位论文
源URL	[http://ir.iee.ac.cn/handle/311042/6698]
专题	电工研究所_其他部门_其他部门_博士学位论文
推荐引用方式 GB/T 7714	1李文萍,电工研究所. 纳米级多功能聚焦离子束光柱体的研究, 纳米级多功能聚焦离子束光柱体的研究[D]. 中国科学院电工研究所. 2007.

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