1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室，上海 201800
2 超强激光科学与技术重点实验室（中国科学院），上海 201800
极紫外（EUV）光刻是7 nm及以下技术节点芯片大规模量产的关键技术。随着技术节点的减小、工艺复杂性的增加，芯片的良率面临着巨大挑战。边缘放置误差（EPE）是量化多重曝光技术过程中制造图案保真度的最重要指标。EPE控制已成为多重曝光和EUV融合光刻时代最大的挑战之一。EPE是关键尺寸（CD）误差和套刻误差的结合。在EUV光刻中，光学邻近效应和随机效应是引起光刻误差的重要因素。光学邻近效应校正（OPC）可以使EPE最小化。对于最先进的技术节点，EPE通常由随机效应主导，因此需要对EPE进行建模，尤其是需要对随机效应进行严格的建模，以分析影响EPE的关键参数。选择不同的测量手段对关键参数进行测量并优化EPE是提高芯片良率的重要途径。本文首先综述了EPE在EUV光刻中的重要作用，然后讨论了OPC和随机效应、EPE模型及涉及的关键参数，并介绍了关键参数的测量方法，最后总结和展望了与EPE相关的技术。
测量 极紫外光刻光源 套刻 光学邻近效应校正 对准
Author Affiliations
Abstract
1 School of Microelectronics, Shanghai University, Shanghai, China
2 Department of Precision Optics Engineering, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
With the development of high-volume manufacturing for very-large-scale integrated circuits, the purity of the light source in the extreme ultraviolet lithography (EUVL) system needs to fulfil extreme requirements in order to avoid thermal effect, optical distortion and critical dimension errors caused by out-of-band radiations. This paper reviews the key technologies and developments of the spectral purity systems for both a free-standing system and a built-in system integrated with the collector. The main challenges and developing trends are also discussed, with a view towards practical applications for further improvement. Designing and manufacturing spectral purity systems for EUVL is not a single task; rather, it requires systematic considerations for all relevant modules. Moreover, the requirement of spectral purity filters drives the innovation in filtering technologies, optical micromachining and advanced metrology.
collector mirror extreme ultraviolet lithography spectral purity filter High Power Laser Science and Engineering
2023, 11(5): 05000e64
Author Affiliations
Abstract
1 School of Microelectronics, Shanghai University, Shanghai 200072, China
2 Department of Precision Optics Engineering, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Overlay (OVL) for patterns placed at two different layers during microchip production is a key parameter that controls the manufacturing process. The tolerance of OVL metrology for the latest microchip needs to be at nanometer scale. This paper discusses the influence on the accuracy and sensitivity of diffraction-based overlay (DBO) after developing inspection and after etching inspection by the asymmetrical deformation of the OVL mark induced by chemical mechanical polishing or etching. We show that the accuracy and sensitivity of DBO metrology can be significantly improved by matching the measuring light wavelength to the thickness between layers and by collecting high-order diffraction signals, promising a solution for future OVL metrology equipment.
diffraction-based overlay overlay metrology accuracy lithography semiconductor microchip Chinese Optics Letters
2023, 21(7): 071204
1 北京邮电大学信息光子学与光通信国家重点实验室，北京 100876
2 中国科学院半导体研究所，北京 100083
本课题组设计了一种用于硅基外延激光器的对称负极芯片结构，与传统共面电极芯片结构相比，该结构大幅降低了硅基激光器的微分电阻，使激光器性能显著提升。采用该电极结构以及基于无偏角Si（001）衬底的量子点激光器外延材料进行了激光器芯片制作。芯片尺寸为1500 μm×50 μm的激光器的微分电阻仅为1.52 Ω，单面输出光功率可达70 mW。实验结果表明：相比于传统共面电极芯片结构，该芯片结构可将器件的微分电阻降低约75%；当注入电流从1.2倍阈值电流增大到2.8倍阈值电流时，激射波长红移量减少了约77%，特征温度由27.2 K提高到43.4 K，斜率效率增大了约26.4%，最大光电转换效率增大了约4.7倍。所设计的芯片结构方案为制作高性能硅基外延激光器提供了一种优化的技术途径。
激光器 硅基激光器 直接外延 对称负极结构 微分电阻 中国激光
2023, 50(11): 1101019
为了研究复合涂层中碳化钨(WC)组织演变对裂纹产生的影响机理, 采用单层激光熔覆、过渡层梯度熔覆与双层熔覆制备 3种 Ni50A/WC复合涂层对比的方法, 分析涂层的形貌与组织、裂纹产生特点以及原因, 探究WC的组织演变对裂纹产生的影响。结果表明, 不同熔覆方法的WC组织演变对裂纹产生的影响主要由残余WC颗粒内部开裂形成裂纹源、硬质相元素引起成分偏析等作用组成; 双层熔覆、梯度熔覆涂层与单层熔覆涂层相比, 由于粉末吸收了更多的能量, 残余WC颗粒含量降低了32.7%与37.9%, 减少了涂层内部裂纹源; 共晶化合物的W元素质量分数也从单层熔覆涂层的0.534分别下降到双层熔覆涂层的0.417与梯度熔覆涂层的0.386, 降低了硬质相元素集中程度, 减少了涂层成分偏析, 降低了涂层开裂敏感性。该研究对改善激光熔覆复合涂层的开裂问题、提高复合涂层的成品率有一定的指导意义。
激光技术 复合涂层 组织演变 裂纹 碳化钨 laser technique composite coating microstructural evolution crack WC
上海理工大学 光电信息与计算机工程学院，上海 200093
为了设计用于光频域反射仪（optical frequency domain reflectometer, OFDR）温度传感的涂层光纤，提升OFDR的温度灵敏度，增加其适用场景，从理论上分析了 1 层和 2 层涂层对单模光纤中瑞利频移温度灵敏度的影响并进行了仿真。考虑到外涂层的几何、热和机械性能，首先，用Lame解理论分析涂层对OFDR瑞利频移温度灵敏度的影响；其次，基于温度带来的光纤轴向应变关系以及光纤与 1 层涂层之间的力平衡，提出了仅含 1 层涂层的简化解；最后，针对建立的理论模型，对 1 层以及 2 层外涂层光纤的瑞利频移温度灵敏度进行了仿真。结果表明，瑞利频移温度灵敏度随着外涂层的杨氏模量、半径和热膨胀系数的增加而增加，而与涂层泊松比几乎无关。本研究结果将有助于提高OFDR在高温度灵敏度和低温场景中的应用。
光纤 涂层 光频域反射仪 温度灵敏度 fiber coating optical frequency domain reflectometer temperature sensitivity
Author Affiliations
Abstract
Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, P. R. China
Background: Lung cancer is one of the most common malignant tumors worldwide. Currently, effective screening methods for early lung cancer are still scarce. Breath analysis provides a promising method for the pre-screening or early screening of lung cancer. Isoprene is a potential and important breath biomarker of lung cancer. Material and Methods: To investigate the clinical value of isoprene for diagnosing lung cancer patients, a cavity ringdown spectroscopy (CRDS) based near-real time, sensitive analysis method of breath isoprene is developed in our lab. In this paper, 92 breath samples from lung cancer patients, 17 breath samples from patients with benign lesions, and 107 breath samples from healthy people were collected. Results: Research indicates that breath isoprene concentration is significantly higher in healthy individuals (ppbv) than in patients with lung cancer (ppbv) and benign lung lesions (ppbv). The result of Receiver Operating Characteristic (ROC) curve suggests that the concentration of isoprene is meaningful for the diagnosis of lung cancer (, , , ). Conclusion: This study demonstrates that the CRDS breath isoprene analysis system can effectively analyze a large sample of human breath isoprene, and preliminarily confirms the use of breath isoprene as a biomarker for lung diseases.Background: Lung cancer is one of the most common malignant tumors worldwide. Currently, effective screening methods for early lung cancer are still scarce. Breath analysis provides a promising method for the pre-screening or early screening of lung cancer. Isoprene is a potential and important breath biomarker of lung cancer. Material and Methods: To investigate the clinical value of isoprene for diagnosing lung cancer patients, a cavity ringdown spectroscopy (CRDS) based near-real time, sensitive analysis method of breath isoprene is developed in our lab. In this paper, 92 breath samples from lung cancer patients, 17 breath samples from patients with benign lesions, and 107 breath samples from healthy people were collected. Results: Research indicates that breath isoprene concentration is significantly higher in healthy individuals (ppbv) than in patients with lung cancer (ppbv) and benign lung lesions (ppbv). The result of Receiver Operating Characteristic (ROC) curve suggests that the concentration of isoprene is meaningful for the diagnosis of lung cancer (, , , ). Conclusion: This study demonstrates that the CRDS breath isoprene analysis system can effectively analyze a large sample of human breath isoprene, and preliminarily confirms the use of breath isoprene as a biomarker for lung diseases.
Cavity ringdown spectroscopy breath isoprene early diagnosis of lung cancer Journal of Innovative Optical Health Sciences
2022, 15(5): 2250029
为了研究紫外皮秒激光在均热板基板表面刻蚀微沟槽后, 不同激光工艺参数对微沟槽表面疏水性的影响规律, 采用Cassie-Baxter模型进行了理论分析, 并利用单因素实验法, 改变激光扫描速率、激光扫描间距、光斑横向重叠次数进行实验验证。结果表明, 降低固-液区域面积占比、宽度或缩短沟槽间距, 均可以提升微沟槽表面的疏水性能; 造成微沟槽表面疏水的主要原因是其内部的微纳结构以及加工时吸附的疏水性化学基团; 当激光扫描速率为125mm/s、激光扫描间距为200μm、光斑横向重叠次数为2次时, 紫外皮秒激光刻蚀出的微沟槽表面的疏水性最强。该研究为增强均热板冷凝端的疏水性能、提升其整体循环效率提供了参考。
激光技术 激光刻蚀 皮秒激光 微沟槽 疏水性 laser technique laser etching picosecond laser microgroove hydrophobic
