紫外显微镜微纳线宽测量关键技术的研究

发布时间：2019-06-02 03:22

【摘要】：现在在半导体集成电路制造业中,晶体管的线宽尺寸已达到65nm与32nm,并正在向22nm甚至16nm尺寸迈进。当线宽单位缩小到10nm量级时,测量将进入到“关键尺寸”的范围,相应的微纳几何尺寸测量值及测量不确定度对目前的测量技术提出了巨大的挑战。为此中国计量科学研究院正在研究一套计量型紫外光学微纳几何结构计量标准装置,用于对掩膜板线宽的测量及溯源。论文着重对其中的微纳线宽测量关键技术进行了研究,并根据研究的内容,分别构建了一套显微镜自动对焦系统和光电倍增管信号放大与处理系统,最终通过两者的协同作用成功的实现了线宽轮廓信号的提取和测量。论文的工作分为以下几个方面：1、研究了计量型紫外光学显微镜的整体架构以及基于光电倍增管光电转换效应的微纳线宽测量原理和相应的分光光路结构设计,引出了线宽测量所涉及的两个重要的电气控制系统一自动对焦系统和光电倍增管信号放大处理系统。2、介绍线宽测量过程中自动对焦系统的设计。硬件方面主要包括硬件结构的设计和相应部件选取；软件方面则着重介绍了对焦评价函数的选取、对焦窗口及搜索策略的选取,通过对比不同的对焦评价函数的评价效果,最终选取基于小波分解的对焦评价函数。在软件实现方面,利用VC与MATLAB的混合编程的方法,简单有效的实现图像的小波分解,进而实现图像的清晰度评价。3、介绍了光电倍增管信号放大处理系统的设计。通过对光电倍增管所接收光强的分析,最终选取滨松H11461-09光电倍增管模块作为系统的光电转换器件。由于所选用的光电倍增管的输出信号为微弱的电流信号,所以为满足后续电路的采样需求,设计了一款基于电流负反馈的微弱信号放大器,最终实现将线宽的光强信号转换为模拟电压信号。4、通过结合前面所研究的自动对焦系统和光电倍增管信号放大处理系统,构建了一套微纳线宽测量系统。利用该系统对标准栅格样板进行扫描测量,最终验证了本文所设计的线宽测量方法的可行性和精确性。
[Abstract]:Now in the semiconductor integrated circuit manufacturing industry, the linewidth size of transistors has reached 65nm and 32 nm, and is moving towards 22nm and even 16nm dimensions. When the linewidth unit is reduced to the order of 10nm, the measurement will enter the range of "key size". The corresponding micro-nano geometric size measurement value and measurement uncertainty pose a great challenge to the current measurement technology. For this reason, the China Academy of Metrology is developing a set of metrological ultraviolet optical micro-nano geometric structure measurement standard device, which can be used to measure the linewidth of the mask plate and trace it back to the source. In this paper, the key technologies of micro-nano linewidth measurement are studied, and according to the research content, a set of microscope automatic focusing system and photomultiplier tube signal amplification and processing system are constructed respectively. Finally, the extraction and measurement of linewidth profile signal is successfully realized through the synergy of the two. The work of this paper is divided into the following aspects: 1. The overall structure of metrological ultraviolet optical microscope and the principle of micro-nanowatt linewidth measurement based on photomultiplier tube photomultiplier effect and the corresponding structure design of spectroscopic path are studied. Two important electrical control systems, automatic focusing system and photomultiplier tube signal amplification processing system, are introduced. 2. The design of automatic focusing system in the process of linewidth measurement is introduced. The hardware mainly includes the design of hardware structure and the selection of corresponding components. In the aspect of software, the selection of focusing evaluation function, focusing window and search strategy are introduced emphatically. by comparing the evaluation results of different focusing evaluation functions, the focusing evaluation function based on wavelet decomposition is finally selected. In the aspect of software implementation, the wavelet decomposition of the image is realized simply and effectively by using the mixed programming method of VC and MATLAB, and then the definition evaluation of the image is realized. 3, the design of the signal amplification and processing system of photomultiplier tube is introduced. Based on the analysis of the light intensity received by the photomultiplier tube, the module of the photomultiplier tube is selected as the photoelectric conversion device of the system. Because the output signal of the selected photomultiplier tube is a weak current signal, in order to meet the sampling requirements of the following circuit, a weak signal amplifier based on negative current feedback is designed. Finally, the optical intensity signal of linewidth is converted into analog voltage signal. 4. a set of micro-nanowatt linewidth measurement system is constructed by combining the automatic focusing system and photomultiplier tube signal amplification and processing system studied above. The system is used to scan and measure the standard grid template, and the feasibility and accuracy of the linewidth measurement method designed in this paper are verified.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH742

【相似文献】