| 题名 | 高端光刻机照明系统智能均匀性校正技术研究 |
| 作者 | 程伟林 |
| 文献子类 | 博士 |
| 导师 | 黄惠杰 |
| 关键词 | 高端光刻机照明系统 Advanced lithographic illumination 智能均匀性校正技术 intelligent uniformity correction 手指阵列式均匀性校正技术 finger arreys uniformity correction 阵列式手指驱动技术 finger array driving technology |
| 其他题名 | Research on Intelligent Uniformity Correction of Illumination System in Advanced Lithography |
| 英文摘要 | 集成电路是信息化产业的核心，是支撑全球经济社会发展和保障国家安全的战略性、基础性和先导性产业。虽然我国集成电路产业发展的黄金时期已经到来，但是依然面临关键芯片的制造技术严重缺失的局面，高端光刻技术几乎被荷兰的ASML、德国的Zeiss、日本的Nikon 和Canon等垄断。因此，大力研发高端光刻技术是实现我国集成电路产业发展战略布局的必经之路。 照明系统是光刻机的一个核心部件，其功能是通过对照明光场的空间分布和角谱分布进行严格控制为掩模提供成像曝光所需的照明模式与照明光场。早期的步进式光刻机，需确保照明光场内每个视场点的能量一致。但随着光刻机进入扫描曝光时代，硅片表面任一视场点的曝光剂量是照明光场在扫描方向上的能量积分，照明光场在扫描方向的积分沿非扫描方向的分布直接影响分辨率均匀性，所以照明积分均匀性成为光刻机照明系统的关键性能指标之一。为了统一概念，照明均匀性特指照明积分均匀性。为了提高照明均匀性，均匀照明技术被应用于照明系统中，但随着光刻分辨率的不断提高，现有均匀照明技术已不能满足高分辨率的曝光需求，照明均匀性校正技术随之被引入到照明系统中。照明均匀性校正技术从静态灰度滤波法、动态灰度滤波法，发展到手指阵列式校正法，其中手指阵列式照明均匀性校正技术具有校正精度高、灵活度高、可编程等优点，已成为高端光刻机照明均匀性校正的主流技术。因此，本文对手指阵列式均匀性校正技术进行了研究，主要研究内容如下： 1、阐明了手指阵列式均匀性校正技术的原理，分析了照明均匀性校正对照明光瞳性能参数的影响，提出了一种基于逐步逼近式的智能化均匀性校正算法，将该校正方法应用于光刻机照明系统中，仿真结果表明校正后的照明均匀性优于0.3%，能够满足ArF-65nm节点光刻机照明均匀性的需求。 2、在手指阵列式均匀性校正方法应用于光刻机的过程中，校正效率、校正精度是主要的研究重点。针对手指阵列式均匀性校正方法校正效率低的问题，本文提出了一种多自由度均匀性校正方法，该方法在照明条件发生变化，且不改变校正手指伸入照明光场的距离的情况下，通过改变校正手指的离焦量，使得校正后照明均匀性满足指标要求，避免了标定不同照明条件下每个校正手指的作用函数，提高了校正效率。 3、针对手指阵列式均匀性校正方法校正精度低的问题，提出了一种手指阵列错位排布均匀性校正方法。该方法在不增加校正手指数量的前提下，通过优化校正手指前端的形状及其排布方式，提高了校正精度。仿真研究表明双层倒斜角校正手指错开排布均匀性校正精度比常规手指阵列式均匀性校正精度提高了一倍。 4、利用手指阵列式均匀性校正方法进行照明均匀性校正时，通常每个校正手指伸入照明光场的距离均不同，因此手指阵列在照明光场中形成的校正轮廓线为不连续的曲线段，导致校正后的照明均匀性分布为锯齿状的非连续曲线，限制了该方法的校正精度。因此，本文提出了一种轮廓线连续可变均匀性校正方法，该方法中校正轮廓线由一个柔性薄板受载变形后的挠曲线构成。通过控制柔性薄板截面上节点的位移，改变挠曲线的形状，实现校正轮廓线连续可变。通过合理设定节点的位移，校正后的照明均匀性分布为一条近乎水平的平滑曲线，与常规手指阵列式均匀性校正方法的校正精度相比，轮廓线连续可变均匀性校正方法的校正精度提高了约50%。 5、为了将论文论述的校正方法应用于国产化浸没式光刻机中，研制了一套智能化均匀性校正实验装置。其中的阵列式音圈电机可驱动29个校正手指，该电机具有体积小、结构紧凑、响应速度快、定位精度高等优点；校正手指采用双层倒斜角校正手指错开排布的设计。在ArF-90nm光刻机照明系统上进行了均匀性校正实验研究，实验结果显示校正后的照明均匀性优于0.25%，满足浸没式照明系统的照明均匀性指标要求。; The integrated circuits (IC) industry has gradually become the core of the information industry. It is a strategic, basic and leading industry to support the development of the global economy and society and ensure the security of the country. Although the golden age of the development of China's IC industry has come, it still faces the serious lack of cutting-edge core chip manufacturing technology, such as advanced photolithography that is almost monopolized by ASML in Holland, Zeiss in Germany, Nikon and Canon in Japan, and so on. Therefore, vogoriously developing on the advanced photolithography is the only way to achieve the strategic layout of China's IC industry. The illumination system is a core component of the lithography, which provides a uniform illumination field and pupil for the mask to be imaged by strictly controlling the spatial and angular distribution of the ray. In the early step lithography, the exposure dose of each field point should be the same. With the advent of the step-and-scan lithography, however, the exposure dose of each field point is the integration energy of the illumination field in the scanning direction. The illumination integrated uniformity in the scanning direction affects the lithographic Critical dimension uniformity (CDU). Therefore, illumination integrated uniformity has become one of the most critical performance parameters of illumination system in photolithography. To be specified, the following illumination uniformity refers to the illumination integrated uniformity in particular. Illumination homogenization technology is applied in illumination system to promote the uniformity of the field. With the improvement of lithography resolution, the illumination homogenization technology can’t meet the requirement of the illumination uniformity, so illumination uniformity correction technology has been introduced into illumination system. It has developed from static gray filter, dynamic gray filters to finger arrays uniformity correction. The finger arrays uniformity correction is characteristic by better correction accuracy, high flexibility and programmability, and has become a mainstream uniformity correction technology in lithograpgies. Therefore, this dissertation develops research on the uniformity correction technology of illumination system, and main contents are as follows: 1、Chapter 2 makes an in-depth research on finger arrays uniformity correction technology, including expounding Schematic diagram, analyzing the influence of uniformity correction on the performance parameters of the pupil, and then proposing an intelligent uniformity correction algorithm based on gradual approximations to lithography. Simulation results show that the corrected illumination uniformity is superrior to 0.3%, which meets the requirements of illumination uniformity for 65nm node lithography. 2、In the application of the finger arrays uniforminty correction, correction efficiency and correction accuracy are the major research priorities. In the view of the low correction efficiency, a multi-degree of freedom uniformity correction method of lithography illumination system is proposed. When the illumination condition changes, the proposed method can make the corrected illumination uniformity meet the requirements, by tuning the whole fingers along the direction of the optical axis and without changing the distance of the fingers inserted into the field. It avoids the calibration of the correction function of each finger in different illumination condition, which promote the correction efficiency. 3、In the view of the low correction accuracy, a staggered finger arrays uniformity correction method is proposed. The correction accuracy is enhanced by optimizing the fingers’fore-end shape and arrangement of the fingers without increasing the number of fingers. Simulation results show that the correction accuracy of the uniformity correction method with staggered, chamfer and double layout fingers is twice higher than that of uniformity correction with general finger arrays. 4、When finger arrays are inserted into the field to correct the illumination uniformity, the distance of each finger is usually different. The contour curve constituted by the fingers’ fore-end profile is discontinuous, which leads the corrected uniformity to be a serrated curve, and limits the correction accuracy. Therefore, a continuous variable contour uniformity correction method is proposed. In the proposed method, the continuous variable contour is made up of a deflection curve of a deformed flexible thin plate, and the shape of the deflection curve is changed by controlling the displacement of the nodes on the section of the flexible thin plate. By reasonably setting the displacement of nodes, the corrected illumination uniformity can be distributed to a nearly horizontal smooth curve. Compared with the correction accuracy of the uniformity correction with general finger arrays method, the correction accuracy of the continuous variable contour uniformity correction method is increased by about 50%. 5、To apply the uniformity correction method into domestic lithography, a experimental device of intelligent uniformity correction has been made. In the experimental device, the voice coil motor array can drive up to 29 fingers or nodes, and is characrictic by small volume, compact structure, fast response speed and high positioning accuracy and so on. In addition, fingers in the intelligent uniformity correction are designed with staggered, chamfer and double layout. Finally, a experiment of intelligent uniformity correction is carried out on the ArF-90nm lithographic illumination system. The experimental results show that the corrected illumination uniformity is superrior to 0.25%, which meets the requirement of the uniformity of the immersion illumination system. |
| 学科主题 | 光学工程 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31109]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 程伟林. 高端光刻机照明系统智能均匀性校正技术研究[D]. |
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