【作者】 张兴强；

【导师】 王骐；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2008， 博士

【摘要】 极紫外光的波长越短,与软X射线的谱区重叠越多。在波长重叠的区域内,由于光束相干性的缘故,同样波长的辐射有时称为极紫外光,有时称为软X射线激光,这可能源于人们的习惯。无论称谓如何,这些短波长光源的获得主要来自于高温高密度等离子体的辐射。毛细管放电装置将电能直接转化成等离子体的辐射能,能量转换效率较高。软X射线激光的波长短,获得软X射线激光需要很高的泵浦能量;软X射线激光很容易被物质吸收,建立激光谐振腔几乎不太可能。这些不利因素长期制约着软X射线激光器的研制,特别是小型、台式、高效、经济、实用的软X射线激光器。毛细管放电软X射线激光装置的建立和成功运行,打破了禁锢其发展的坚冰,有望建成真正实用的小型高效软X射线激光器。本文在介绍X射线激光基本理论的基础上,利用实验室已出光的毛细管放电软X射线激光装置,在前期研究工作的基础上,进一步深化了软X射线激光研究。开展了预-主脉冲延时对激光输出的影响、低气压下产生激光的主脉冲电流阈值、46.9nm激光谱线的辨认等实验。发现了产生激光的预-主脉冲延时范围和最佳延时段,并揭示了预-主脉冲延时与气压的关系;在28~46Pa的氩气气压下,找到了产生激光的主脉冲电流阈值为~19kA;成功辨认了毛细管放电类氖氩46.9nm激光谱线。通过改变主开关结构,研究了主开关电感对激光输出的影响。主开关支座改进后,电感下降了15%,主脉冲电流平均提高了4%,激光平均输出提高了31%,同时继承了改进前的高耐压性和出光稳定性。毛细管放电检测转接室设计将不仅能够同步检测激光能量和激光谱线,而且有可能大大提高检测的准确性。极紫外光刻技术是目前国际上的研究热门之一,使用波长很短的极紫外光将掩模板上的电路图形缩小成像在光致抗蚀剂上,不用借助分辨率增强技术,即可获得30nm以下的分辨率,有望替代ArF浸没式光刻而成为下一代光刻技术的主流。毛细管放电极紫外光源具有较高的输出功率及能量转换效率,是极紫外光刻的首选曝光光源之一。本文对毛细管放电极紫外光源的重要参数和放电条件进行了定性计算,以便为毛细管放电极紫外光源演示装置的研制提供参考。之后作者全程参与了毛细管放电极紫外光源装置的设计、安装、调试、验收及开展的气体介质放电极紫外辐射研究等工作。通过对真实负载的放电试验,预脉冲电源的放电电压~7kV,电流40~60A,可单次和1~200Hz重复频率工作;主脉冲电源的放电电压~30kV,电流20~40kA,也可单次和1~200Hz重复频率工作,各项放电参数达到了设计标准。在整套装置验收合格的基础上,利用已经标定的罗兰园谱仪,开展了毛细管放电极紫外光谱实验研究,观察到Ar7+、He+离子30nm左右的极紫外光辐射。最终证实:已建成的毛细管放电极紫外光源演示装置安全可靠、运行稳定,等离子体辐射光谱基本位于极紫外目标区,可以开展进一步的极紫外光输出实验。国际上有很多科研小组或团体进行极紫外光刻光源的研究,随着研究的深入,极紫外光刻光源的输出功率不断增大,目前已经达到了应用标准。但高功率光源的获得依赖于极高的重复工作频率,单次输出功率并不高。高重复频率工作对光刻过程及环境有很高的要求,这不仅增大了光刻过程的难度,而且提高了生产成本。本文提出了毛细管放电三束等离子体极紫外环带光源的设计,正是为了解决光刻光源单次输出功率小的问题。通过对毛细管放电三束等离子体形成环带光源的过程进行受力分析,定性计算了环带光源的输出参量等比较全面的设计、论证。结果表明:在相同放电总电流条件下,三束等离子体环带光源的发光体积是常用毛细管的~10倍,光源的最佳收集角提高了~60%,能量转换效率提高了~5倍。这些定性结果预示着毛细管放电三束等离子体极紫外环带光源将有着很大的研发潜力,基础预研还有待继续深化。本论文理论、装置和实验并重,在已出光的毛细管放电软X射线激光装置上开展了进一步的实验研究;参与建立了国内首台毛细管放电极紫外光刻光源演示装置;提出了毛细管放电三束等离子体高功率(单次工作)极紫外环带光源的设计方案。这些成果为今后毛细管放电极紫外光源的深入研究奠定了坚实的基础。更多还原

【Abstract】 The wavelength of extreme ultraviolet (EUV) radiation is so short that it overlaps with soft X-ray spectral band. Within the overlap band, due to its coherence effect, the radiation with the same wavelength is sometimes called as EUV light, but at some occasion as soft X-ray laser, which maybe owing to people’s oral habit. Whatever name it is, the short wavelength source comes mainly from emission of high-temperature and high-density plasma. It is the capillary discharge setup which produces higher conversion efficiency of energy that directly transforms electric power to plasma emission energy.A great deal of pumped energy has to be used in obtaining soft X-ray laser emission with short wavelength. It is almost impossible to build resonance chamber for soft X-ray laser because of intense reabsorption by materials. These adverse factors have restricted the development of soft X-ray laser for a long time, especially those lasers with advantages such as small-size, tabletop, high-efficiency, cost-effective and practicability. However, Establishment and successful operation of capillary discharge soft X-ray laser device smashed the developmental durance, which could hopefully realize truly-applied and small-sized and high-efficient soft X-ray laser. In this dissertation, based on the introduction of elemental theory of X-ray laser, the experimental work concerning extensive research on the basis of prophase working uses the capillary discharge soft X-ray laser equipment at our laboratory. The experiment includes studying effect of time delay of mainpulse current on laser output, probing the mainpulse current threshold with lasing at low Ar pressure and identifying 46.9nm laser spectrum. It is discovered from experimental data that there exists a good time delay range corresponding to lasing in which includes an optimal range corresponding to larger lasing. In the meantime, The experimental result also illustrates the relationship between the time delay and Ar pressure, finds out the mainpulse current threshold of ~19kA with lasing at Ar pressure of 28~46Pa and identifies the 46.9nm laser spectrum in capillary discharge. By modifying the main-switch support, impact of the main-switch inductance on lasing is investigated. After its modification, the main-switch inductance decreases by 15%, the average mainpulse current increases by 4%, the average laser output improves by 31%, and at the same time it inherits the high-voltage endurance and lasing stability before modification. As a supplement, the dissertation provides the design plan for measurement and detection shifting chamber in capillary discharge which will not only survey laser energy and spectrum, but possibly improve experimental precision greatly as well.Extreme ultraviolet lithography (EUVL) technology is one of the popular researches at present, which reduces the circuit pattern in the mask onto photoresist layer by using very short wavelength EUV light. It can obtain resolution width below 30nm by no help of resolution factor enhancement technology, which will be the possible candidate for replacing ArF immersion lithography and become the mainstream of next generation lithography technology. It is the capillary discharge EUV source that exhibits higher output power and conversion efficiency of energy. In this paper, some qualitative calculation of the important parameters and operating condition of capillary discharge EUV source are made in order to provide references to its establishment. After that, the author participates in the work of designing, installation, debugging and checking of the setup and later engages experimental research for EUV emission with gas medium. By discharging to real load, it is discovered that the voltage and current of prepulse source attain ~7kV and 40~60A respectively, and those of mainpulse source attain ~30kV and 20~40kA respectively. Furthermore, both of them can work at one time or at repetition rate of 1~200Hz, which manifests that all kinds of discharge parameters conform to the designing standard. When the setup is completed, the EUV spectrum in capillary discharge by calibrated Rowland circle spectrometer is studied, and the EUV emission of Ar7+ and He+ ions around 30nm are found from experimental result. The experimental data confirms that the plasma emission spectrum lies in the EUV objective zone and the built-up capillary discharge EUV demonstrative setup works safely and stably which can be used to perform the next experiment with EUV output.There are many research groups and organizations of the world working on EUVL source research. With development of investigation, the output power of EUV source increases gradually, and have attained the standard for application. However, the high power source depends mostly on very high repetition rate while the single output energy is not big enough. Still more, the extremely high frequency of operation makes lithographic process difficult and environment rigid which gives rise to cost of ownership. In this dissertation, the design scheme of capillary discharge three-plasma EUV loop source is brought forward so as to solve the problem of the singly less output power of lithographic source. By analysis of force in the process of loop source formation of three-plasma in capillary discharge, the output parameters, comparatively comprehensive design and demonstration, are calculated qualitatively. The result demonstrates that, under the same total current condition, the emission volumn of three-plasma loop source increases as ~10 times big as normal capillary, and the optimal collection angle of it enlarges by ~60% and conversion efficiency of power enhances ~5 times. These qualitative result indicate that capillary discharge three-plasma loop source exhibits great investigative potential but the basic research needs to be continue.The dissertation pays equal attention to the theory, setup and experiment. It is known from the paper that more detail experimental study are carried out with the lasing capillary discharge soft X-ray laser equipment, the first new capillary discharge EUVL source demonstrative setup is made, and the design scheme of capillary discharge three-plasma high-power (single operation) EUV loop source is put forward. These productions set a solid base on thorough research of capillary discharge EUV source in the future.更多还原