基于高次谐波的高功率高稳定13.5 nm极紫外光源

doi:10.3788/CJL231507

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	基于高次谐波的高功率高稳定13.5 nm极紫外光源
其他题名	High Power and High Stability 13. 5 nm Extreme Ultraviolet Light Source Driven by High⁃Order Harmonics
	李逵 1,2; 孟润宇3,4 ; 李睿晅 1,2; 张光银 1,2; 姚铭杰 5; 徐豪 1; 王雨童 1; 李捷 1,2; 张晓世 1,3; 樊仲维 2
发表期刊	中国激光/Chinese Journal of Lasers
	2024-04
卷号	51 期号:07 页码:172-179
DOI	10.3788/CJL231507
分类号	O434
产权排序	第4完成单位
收录类别	EI ; 核心 ; CSCD
关键词	激光器高次谐波极紫外激光 13.5 nm光源软X射线飞秒激光
摘要	开发了由高重复频率（3 kHz）高能量（3 mJ）钛蓝宝石激光器驱动的极紫外和软X射线高次谐波激光光源。该光源系统在30 nm（光子能量为～45 eV）波长附近实现了大于120μW的平均功率，在13.46 nm波长（光子能量为～92 eV）处实现了1.9μW的平均功率，其中在13.46 nm波长处带宽为0.124 nm的单个谐波实现了0.32μW的平均功率。此外，在该系统中，激光功率连续12 h的不稳定性均方根小于5%，连续8 h光束指向均方根小于10μrad。该系统在生物成像、干涉光刻和芯片检测等领域中具有重要应用。
其他摘要	Objective Short wavelength, shortpulse, and highcoherence laser sources are urgently needed for research on ultrawide dynamics at the microscopic scale. Additionally, with the demand for an ever- increasing chip computing speed, the semiconductor field urgently requires small and lowcost extreme ultraviolet light sources for material development and wafer defect detection. Highorder harmonic (HHG) technology is used to realize laboratory desktop applications and produce highcoherence and highresolution extreme ultraviolet (EUV) light sources, which is one of the most reliable technologies and is gradually becoming one of the most important tools for atomic, molecular, advanced quantum, and other materials research as well as nanoimaging. Based on the semiconductor field and experimental requirements, we build a set of HHGEUV sources using a commercial Ti∶sapphire laser, which is a highly stable, highpower 13. 5- nm source. This will advance research in material development, semiconductor performance characterization, biomedical imaging, wafer defect detection, and other fields of research. Methods Highorder harmonic processes can be explained by the semiclassical threestep model, and several experiments have demonstrated that Ti∶sapphire lasers are among the best driving sources for generating an EUV source. Focused highaveragepower laser pulses interacting with rare gases produce harmonics that cover the extreme ultraviolet(UV)and soft Xray regions, thereby making them the most efficient source for electrodynamics studies. The reaction region is commonly characterized using nozzles, gas cells, and hollow waveguides. The latter has the highest harmonic conversion efficiency owing to the phase modulation process; however, it is difficult to calibrate and achieve a stable output over long periods. To achieve a high flux and stable output from a 13. 5- nm harmonic source, we design and build a beam stabilization control system to assist the alignment process and maintain beam stability. In addition, we build a dualoptical and flatfield spectrometer that can effectively optimize the harmonic aberration in the harmonics generated by the device. Results and Discussions When helium is used as the generation gas, the spectral distribution around 13. 46 nm is filtered with Zr films. A calibrated photodiode is used to measure the optical power signal, and the total power generated by the light source is calculated as approximately 1. 9 μW. The spot shape is captured using complementary metaloxide semiconductor (CMOS) at a distance of 1. 9 m from the light source [Fig. 2(b)], and the 1/e2 spot size is calculated to be 1. 92 mm×1. 67 mm with the xdivergence fullangle of the spot calculated to be 1. 01 mrad, and the ydivergence fullangle of the spot calculated to be 0. 88 mrad. When argon is used as the generation gas, two 250- nm thick Al films are used for spectral filtering, and the spectral distribution is around 30 nm. The calculated average power is 120 μW at the light source. Furthermore, in order to measure the pointing and power stability of the EUV beams, a CMOS is placed at a distance of 1. 9 m from the light source. The rootmeansquare (RMS) of the pointing stability is then calculated using the offset of the spot center from the initial position over a 12- h period, with the pointing offset of the beam in the x- direction controlled to within 6. 3 μrad and that in the ydirection controlled to within 7. 2 μrad. The average RMS power stability over a 12- h period is 4. 37%. Wavelength calibration is performed using an inhousedesigned dualoptics flatfield spectrometer with Al and Si films, as shown in Fig. 4(b), which demonstrates the filtered HHG spectral signals of the different films collected using a grating with groove density of 500 line/mm. With the help of the steep absorption edge of the Si film at approximately 12. 5 nm (the absorption peak of the Ai film is at approximately 17. 05 nm), the position of the 59th harmonic peak at 13. 46 nm is obtained. Combined with the slit, our flatfield spectrometer can output any chosen harmonic that minimizes the aberration. As shown in Fig. 6, we analyze the first-, second-, and thirdorder diffraction harmonic intensities of the grating acquired by CMOS, which are consistent with the results of the theoretical coupling calculations. We significantly improve the harmonic spectral resolution using a goldplated planar grating with groove density of 1200 line/mm. We determine that the 13. 46- nm harmonic contains an average power of about 0. 32 μW, and that its true bandwidth is less than 0. 124 nm. Conclusions A highpower, highstability HHG source with a spectrum ranging from 10 nm to 40 nm is developed based on an inflatable hollow optical waveguide using a titanium gemstone laser as the driving light source. Using helium or argon as the reaction gas, multiple harmonics covering 10 nm to 40 nm are obtained, and the total power can be as high as 120 μW. Combined with an inhouse designed dualoptics flatfield spectrometer and a monochromator, a single harmonic with an average power of about 0. 32 μW, a bandwidth of about 0. 124 nm and a center wavelength of 13. 46 nm is obtained. The engineering design is adopted for the system and a technical breakthrough for this type of light source in terms of the pointing stability and power stability index is therefore successfully realized, which are worldleading results. Our study lays a solid foundation for the application and promotion of this light source in the industry. This light source will be popularized and validated in the fields of EUV interference lithography experiments, photoresist research and development, material parameter measurements in EUV lithography technology, nanometer or quantum material research and development, and semiconductor wafer defect detection.
资助项目	国家重点研发计划[2021YFB3602600]; 国家自然科学基金青年科学基金[62005291]; 中国科学院项目[GJJSTD20200009]; 北京市科学技术委员会项目[Z221100006722008]
项目资助者	国家重点研发计划[2021YFB3602600] ; 国家自然科学基金青年科学基金[62005291] ; 中国科学院项目[GJJSTD20200009] ; 北京市科学技术委员会项目[Z221100006722008]
语种	中文
学科领域	物理学 ; 光学 ; 激光物理
ISSN	0258-7025
URL	查看原文
CSCD记录号	CSCD:7721395
EI入藏号	20241816024833
EI主题词	Extreme ultraviolet lithography
EI分类号	461.1 Biomedical Engineering - 525.5 Energy Conversion Issues - 714.2 Semiconductor Devices and Integrated Circuits - 744.1 Lasers, General - 744.4.1 Semiconductor Lasers - 746 Imaging Techniques - 921.6 Numerical Methods - 951 Materials Science
引用统计
文献类型	期刊论文
版本	出版稿
条目标识符	http://ir.ynao.ac.cn/handle/114a53/27129
专题	南方基地
作者单位	1.中国科学院空天信息创新研究院; 2.中国科学院大学光电学院; 3.云南大学物理与天文学院; 4.中国科学院云南天文台; 5.北京航空航天大学仪器科学与光电工程学院
推荐引用方式 GB/T 7714	李逵,孟润宇,李睿晅,等. 基于高次谐波的高功率高稳定13.5 nm极紫外光源[J]. 中国激光/Chinese Journal of Lasers,2024,51(07):172-179.
APA	李逵.,孟润宇.,李睿晅.,张光银.,姚铭杰.,...&樊仲维.(2024).基于高次谐波的高功率高稳定13.5 nm极紫外光源.中国激光/Chinese Journal of Lasers,51(07),172-179.
MLA	李逵,et al."基于高次谐波的高功率高稳定13.5 nm极紫外光源".中国激光/Chinese Journal of Lasers 51.07(2024):172-179.

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