探针诱导等离子体光刻及压缩感知成像实验研究
文献类型：学位论文
| 作者 | 赵成强 |
| 学位类别 | 博士 |
| 答辩日期 | 2010 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐文东 |
| 关键词 | 光刻 表面等离子体共振 探针 压缩感知成像 |
| 其他题名 | Experiment Study on Probe Inducing Surface Plasmon Lithography and Compressed Sensing Imaging |
| 中文摘要 | 本文内容包括了两部分工作：第一部分是探针诱导等离子体光刻的实验研究，是论文的主要部分，共分为六章进行论述；第二部分是压缩感知成像实验研究，为最近的研究方向，由于研究时间较短，因此只用一章(第七章)对其进行论述。 关于探针诱导等离子体光刻部分，论文首先在绪论中大体介绍了光刻技术的发展情况，以及表面等离子光刻的主要方向和特点；然后，介绍了探针诱导等离子体光刻的主要理论和模型，并通过FDTD数值模拟了光刻的可行性和各种参量的影响；在随后的第三章和第四章中，主要是探针诱导等离子体光刻实验装置的设计和制作，及其控制软件的研制，这些工作为光刻实验研究的顺利进行提供了条件；通过实验获得了光刻图形，并对结果进行分析得到了一些光刻规律；最后总结了本项目的主要内容并对将来的工作进行展望和规划。 探针诱导等离子体光刻是一种新颖的光刻技术，无论是理论上还是实验上都存在一些问题，因此我们做了许多研究工作，工作的内容和取得的一些结果具体可以分为如下几个方面： 1) 根据Kretschmann结构的棱镜耦合全内反射原理，提出了探针诱导等离子体光刻的模型，并设计了金属层/保护层/记录层的光刻材料膜层机构；通过FDTD数值计算，模拟了膜层各种结构对表面等离子共振的影响，最终选择了Ag、SiO2、AgOx分别作为三个膜层的材料；模拟了探针针尖的材料、与记录层的距离以及针尖大小对光刻的影响，确认Ag探针具有最好的局域场增强效果，且与记录层的距离越近越好，而针尖大小则直接决定了光刻图形的最小线宽，这些结论为光刻参量的选择提供了理论依据。 2) 根据前面的模拟和实际使用要求确定了光刻装置的总体结构，并采用模块化的设计完成了实验装置的集成。该系统由光源、表面等离子体激发模块、探针控制和检测模块、光学显微镜组成：光源由一个514.5 nm波长的氩离子连续激光器和声光调制器组成，声光调制器用于控制曝光时间；表面等离子体激发模块采用Kretschmann型结构，该模块中，激光经过扩束后由一个或几个反射镜调整方向，然后经聚焦镜和棱镜后照射在样品表面。在棱镜和样品之间填充折射率油，以防止光在棱镜上发生全反射。扩束镜和聚焦镜配合使用，将激光聚焦成直径小于200 µm的光斑，从而使光能高度集中；探针控制和检测模块在一个AFM基础上改造完成，既可以作为诱导SPR的工具，又可以作为检测光刻结果的工具；光学显微镜的工作距离达到65 mm，放大倍率为5X，用于观察样品以及探针和激光聚焦光点的对准等。 3) 利用LabVIEW软件便捷的图形化语言和自动多线程技术，研制了光刻实验装置的控制软件。软件主程序采用模块化的结构进行设计，通过调用不同的子VI程序完成不同的功能，其优点在于流程清晰、便于程序升级、易于维护。软件主要包括AFM扫描、光刻、电机控制三个主要模块，它们都调用探针控制模块完成探针的控制。AFM扫描模块实现样品表面形貌信息的采集；光刻模块主要分为单点刻蚀和矩阵刻蚀；电机控制模块是一个独立的小功能模块，主要用于AFM扫描和光刻之前控制样品的进给以及任务结束后用于样品退出；探针控制模块是控制软件的基本模块，是前面所述三大模块的基础，本模块中采用了PID反馈算法以及多线程等技术以满足探针的高精度控制。软件还包括了一些图像处理和显示的功能，方便了光刻现象的展示和研究分析。 4) 在光刻实验中，利用原子力探针在样品表面产生了直径100 nm以下的光刻点，并通过研究获得了光刻的一些规律：随着曝光时间的增长和激光功率的增加，光刻点的直径和深度都有增大，但深度的增加比直径要明显；单层结构时，Ag膜厚度在40 nm时光刻效果比较好；激光以共振角入射时能获得较好的光刻结果；通过缩小激光聚焦光斑，能够获得更好的光刻点；通过对多层膜的光刻实验，发现双层膜或三层膜的光刻效果均不理想，且探针的压力也参与了光刻过程。通过实验得到的一个比较重要的结论是：膜层结构在表面等离子体共振光刻中起着非常关键的作用，各个膜层比较薄时可能会有更好的光刻效果。另外，因为Si探针比镀Au探针有更小的针尖，因此其光刻效果更好。 从前面的研究来看，探针诱导等离子体光刻技术离最终的可实用化还有很长的路要走，而且在理论上也需要进一步研究。但是技术本身所具有的加工精细度高、低功耗、工艺简单、设备成本低等优秀的性质仍具有非常大的吸引力，而且这是一种无掩模的纳米加工技术，拥有方便实用的特性。其光刻效率低的问题也可以通过探针阵列或类似飞行磁头的探针控制方法等来解决，因此综合考虑，探针诱导等离子体光刻技术仍有非常好的应用前景。 压缩感知成像是一种非常新颖的成像方式。为了研究其性质，本文中设计了两种方案：傅立叶方案和成像方案，比较了两种方案的优缺点，并最终将两种方案都付诸了实施，最终的效果与理论设想相符合。在实验中通过对一个设计的鉴别率板成像展示了压缩感知成像的超分辨特性，在初步的实验中得到了超过4倍衍射极限的结果。压缩感知成像其他的一些特性和规律以及应用方向还需要进一步研究。 |
| 英文摘要 | The thesis includes two parts. The first one is experimental study on probe inducing surface plasmon lithography, which is the main body and divided into six chapters. The content of the second part is about compressive-sensing imaging, which is my current research subject. As it is spent less time on this part, only one chapter is used to show it. As to the first part, the development status, trend and main characteristics of lithography are reviewed firstly. Then, the main theory and model of probe inducing surface plasmon lithography are shown, and its feasibility and various parameters are confirmed by FDTD simulation. We have designed an experimental instrument and developed its control software, which provided good conditions for the experiment. By the experiment, we have gotten some lithography pattern whose simple rules were analyzed. In the end of this part, the main task is summarized and the future responsibility has been planned. As probe inducing surface plasmon lithography is a relatively new photetch, there are some problems both in theory and practice, so we have done much study work which could be divided into the following aspects: 1) By the total internal reflection theory of Kretschmann structure, the model of probe inducing surface plasmon lithography is put forward，moreover, three-layer film structure, which is metal layer/ protecting layer/ recording layer, has been designed. The effect of film structure to surface plasmon resonance has been simulated by FDTD, and Ag, SiO2, AgOx have been selected as the materials of the three films. The effects of the tip''s parameters, which include material, size and its distance to recording film, have been simulated too. By analysis, Ag tip has the best local enhancement of the electromagnetic field, and the closer it goes to recoding film, the better the lithography performance is. The finest line width of lithography pattern is dependent on the size of the tip directly. All the above conclusions provide theory basis to the choice of lithography parameters. 2) Based on the above simulations and the practical requirements, the general architecture of the experiment device has been designed. The experimental facility consists of light source, surface plasmon excitation module, tip control module and optical microscope. The light source includes an argon-ion laser(=514.5nm) and an acousto-optic modulator which is used to control exposure time. In the surface plasmon excitation module based on Kretschmann structure, the direction of the light beam expanded can be adjusted by one or more mirrors to make it go through a focusing lens and a prism, and then it shoots onto upper surface of the specimen. In order to avoid the occurrence of total reflection at the surface of the prism, oil has been filled between the specimen and the prism. After the beam being expanded and focused, the diameter of the laser spot is about 200μm, which makes a great concentration of laser power. As the tip control module has been accomplished on an AFM, this module can both excites surface plasmon and scans the lithography pattern. The optical microscope, which has 65mm work distance and 4× enlargement ratio, can be used to observe the specimen and aim the laser spot at the tip. 3) The control software for experiment device is developed based on the G language and automatic multi-threading characteristic of LabVIEW. Since the main program is developed based on module architecture, it can realize different functions by calling different sub-VIs, which results in several excellent feathers such as clear progress, easy to upgrade and ease of maintenance. The program mainly includes three modules: AFM scanning, lithography and motor-control module, and all of them control the probe by calling the probe-control module. The AFM scanning module is used to acquire surface topography of specimen. The lithography module includes point etching and matrix etching parts. The motor-control module is an independent functional module, which is used to make specimen approach or move back before and after AFM scanning or lithography. The probe-control module is the base component of the software, which adopts PID feedback algorithm and multi-threading method to control the probe. The software includes some image processing and display functions, which makes it convenient to show and study the results. 4) In the lithography experiment, holes with diameter less than 100nm have been written in the surface of the specimens. And some rules of lithography have been attained as follows. The diameter and depth of the holes written into the specimen both increase along with the increase of exposure time or laser power, however, the depth performs faster than the diameter. With single-layer film, its performance is the best when the depth of Ag film is 40nm. Lithography can be done only when the incidence angle of laser matches the resonance angle. Better patterns can be attained by narrowing the laser spot. In the multi-layer film experiment, lithography effects are unsatisfactory with two-layer films and three-layer films, and the pressure of the probe play a part in lithography process too. It is concluded that the film structure will play a key role in lithography and it will be better if the film is thinner. In addition, since the Si probe has smaller tip than the probe plated with gold, the lithography pattern with Si probe has better performance. It is seen from the previous study that probe inducing surface plasmon lithography still has a long way to go before reaching practicability and its theory is still needed to be study. However, this technology owns many advantages: high precision, low power dissipation, simple technique and low equipment costs, in addition, it is convenient and practical for its maskless characteristic, so it is still very attractive. The efficiency problem of this lithography method can be solved by probe-array or flying-head technique, so it has good prospects by comprehensive consideration. Compressed sensing imaging is a new imaging method. In order to study its characteristic, we have proposed two designs: Fourier scheme and imaging scheme. And, both two designs have been executed. In the experiment, a resolution chart has been designed to show the super-resolution property of compressed sensing, and the actual resolution is more than four times the diffraction limit in the initial study. Further research is still needed for the other characteristics and application fields of compressed sensing Imaging. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15621]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 赵成强. 探针诱导等离子体光刻及压缩感知成像实验研究[D]. 中国科学院上海光学精密机械研究所. 2010. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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