投影光刻机中的线阵CCD高速检焦技术研究

发布时间：2018-01-16 08:11

本文关键词：投影光刻机中的线阵CCD高速检焦技术研究　出处：《中国科学院研究生院（光电技术研究所）》2015年硕士论文　论文类型：学位论文

【摘要】：随着光学投影光刻分辨力的不断提高,投影物镜的焦深在逐渐缩短,通常在百纳米级。为充分利用物镜有限的焦深,高精度的检焦调焦技术成为研究热门。而投影光刻机进入到步进扫描时代以及硅片尺寸的不断增大,使得检焦调焦系统在保证精度要求的情况下,需要同时兼顾检焦调焦的实时性和频率。现有的粗检焦技术多为光度检焦技术,采用四象限探测器或者面阵CCD采集携带有硅片离焦量信息的光强信号。中科院光电所的TYG2000/T型步进投影光刻机采用光度检焦技术,在计算机上进行图像处理完成检焦,最后通过串口控制工件台对离焦量进行补偿。此方法在上位机完成闭环,传输环节冗余,检焦频率低,在工件台步进的过程中不能进行实时的检焦调焦,产率不高。鉴于此,本文提出了一种用线阵CCD采集图像,以FPGA为处理器在下位机完成闭环的检焦方案。此方案利用线阵CCD的高速性和FPGA的并行性,结合亚像素像点定位算法,在保证检焦精度优于1μm、量程大于200μm的条件下,较大幅度提高了检焦频率,在工件台步进的过程中实现了实时检焦,降低了成本,减小了功耗。本文详细介绍线阵CCD下位机闭环高速检焦系统的设计、实验过程。在第一章介绍了光刻技术及检焦技术的研究现状与发展方向;第二章详细介绍了CCD和Camera Link协议的相关知识,在此基础上,展开了系统整体方案的设计和优化;第三章分享了电路板的硬件设计过程及经验教训;第四章分析了图像处理算法的基本理论知识,使用Verilog HDL实现了多种算法,并完成了功能仿真;第五章完成了线阵CCD下位机闭环检焦系统的实验验证工作,实验结果表明,该系统检焦精度优于1μm,行程约为400μm,检焦频率达到1.3KHz,速度有大幅提升,满足设计指标;最后总结与展望部分对本论文所完成的工作做了总结,对下一步研究工作提出了自己的意见。
[Abstract]:With the improvement of the resolution of optical projection lithography, the focal depth of the projective objective lens is gradually shortened, usually at the level of 100 nanometers, in order to make full use of the limited focal depth of the objective lens. High precision focusing and focusing technology has become a hot research, and the projection lithography has entered the step scanning era and the size of silicon wafer is increasing, which makes the focusing and focusing system ensure the accuracy of the system. It is necessary to take into account the real-time and frequency of focusing and focusing simultaneously. Most of the existing coarse coke detection technologies are photometric focusing techniques. Using four-quadrant detector or area array CCD to collect the intensity signal with the information of the defocus of silicon wafer. The TYG2000/T stepwise projection lithography machine of the Institute of Optoelectronics of the Chinese Academy of Sciences adopts photometric focusing technology. Image processing on the computer to complete the focal detection, finally through the serial port control workpiece platform to compensate for the defocus. This method in the host computer to complete the closed loop, transmission redundancy, low focusing frequency. In the process of workpiece stepping, it is not possible to focus and focus in real time, and the yield is not high. In view of this, a linear array CCD is proposed to capture images. Using FPGA as the processor to complete the closed-loop focal detection scheme, this scheme utilizes the high-speed of linear CCD and the parallelism of FPGA, and combines sub-pixel image location algorithm. Under the condition that the accuracy of coke detection is better than 1 渭 m and the measuring range is more than 200 渭 m, the frequency of coke detection is greatly increased, and the real-time detection of coke is realized in the process of workpiece step by step, and the cost is reduced. This paper introduces the design and experimental process of the closed loop high speed focus detection system of linear CCD slave computer. In the first chapter, it introduces the research status and development direction of lithography technology and focus detection technology. The second chapter introduces the related knowledge of CCD and Camera Link protocol in detail. On this basis, the design and optimization of the whole system scheme are carried out. In the third chapter, the hardware design process and the experience and lessons of the circuit board are shared. In chapter 4th, the basic theory of image processing algorithm is analyzed, and a variety of algorithms are implemented with Verilog HDL, and the functional simulation is completed. In Chapter 5th, the experimental verification of the closed loop focal detection system of linear CCD lower computer is completed. The experimental results show that the accuracy of the system is better than 1 渭 m and the stroke is about 400 渭 m. The frequency of coke detection reaches 1.3 KHz, and the speed is greatly improved to meet the design target. In the last part, the author summarizes the work done in this paper, and puts forward his own opinions on the next research work.
【学位授予单位】：中国科学院研究生院（光电技术研究所）
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN305.7

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