【作者】 孟艳丽；

【导师】 陈波；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 光学， 2012， 博士

【摘要】 软X射线-极紫外波段复合型望远镜是空间天气预报以及科学研究的重要仪器。本文围绕Wolter I型掠入射X射线望远镜系统，对望远镜反射镜镜面薄膜密度测定、超光滑表面粗糙度测量、表面异常散射现象进行了研究，为后续工程立项奠定基础。1．研究了畸变波玻恩近似理论及微扰理论，给出了能够从散射分布直接测得表面功率谱函数的一级矢量微扰公式。讨论了一级矢量微扰理论的适用性：测量散射分布时所采用的掠入射角和散射角不能太大，对应不同材料、表面均方根粗糙度σ不应超过1-2.5nm。2．首先介绍了X射线散射分布测量装置。用电子束蒸发法镀制了金薄膜和镍薄膜，用磁控溅射法镀制了钼薄膜，用原子层沉积法沉积了A₂O₃薄膜。应用修正的布拉格方程计算了A₂O₃薄膜厚度，结果表明，原子层沉积薄膜的均匀性、厚度可控性好。最后，利用X射线表面散射特性、给出了一种由X射线反射率曲线精确测量薄膜密度的方法(XRR_DEN)，并对金、镍、钼和A₂O₃薄膜分别进行了测量。为利用X射线散射法准确测量薄膜表面功率谱函数打下基础。3．针对所用的X射线散射测量装置，分析了接收狭缝宽度、入射光束宽度和系统校正误差对测量结果的影响，根据分析结果确定实验参数。测量光学表面及薄膜样品的X射线散射分布，用一级矢量微扰法计算超光滑表面一维功率谱密度（PSD）函数和有效均方根粗糙度，测量结果与原子力显微镜（AFM）所测结果吻合。结果表明，应用一级矢量微扰法可以测量超光滑表面粗糙度。特别地，对于薄膜样品根据XRR_DEN法实测密度值计算光学常数，可以提高一级矢量微扰法的测量精度。4．在掠入射散射法测量超光滑表面和薄膜表面粗糙度的实验过程中,发现存在异常散射现象。波长一定时，表面异常散射的位置与样品的材料有关、与掠入射角和表面粗糙度无关，且总在略小于临界角处，与实测临界角的误差在-8%至-0.3%之间，异常散射随着掠入射角和表面粗糙度的增大更加显著。分析了异常散射产生的原因，分析结果与实验结果一致，为进一步研究异常散射对掠入射系统成像质量的影响奠定基础。更多还原

【Abstract】 The complex space soft X-ray and EUV telescope is mainly applied to the spatialenvironment monitoring and scientific studies for the solar and other celestialactivities. According to the Wolter-I type mirror adopted in this system, thin filmdensity measurement, surface roughness measurement of supersmooth surface andanomalous surface scattering （ASS） phenomenon are studied in detail.1．Distorted wave Born approximation （DWBA） theory and perturbation theory（PT） have been introduced. Furthermore, first order perturbation theory （FOPT）formulas have been deduced to extract power spectral density （PSD） functions of thesurface roughness directly from the measured scattering distribution. At last, theconditions of applicability of FOPT have been discussed. The measurement of thescattering diagram should be carried out at not too large incidence angle andscattering angle. And the RMS roughnessσ does not exceed1-2.5nm, the largervalue corresponding to the case of light materials.2． Firstly, the X-ray scatting distribution measurement facility has beenintroduced. Secondly, Au thin film and Ni thin film have been evaporated by electronbeam coater, Mo thin film has been sputtered by magnetron sputtering coatingmachine, and A₂O₃thin films have been deposited by Atomic layer deposition （ALD）.Thirdly, thin film thickness has been calculated according to the modified Braggequation, which indicates that ALD is a thin film coating method with high uniformityand thickness controllability. Lastly, a simple method to evaluate thin film massdensity accurately from the X-ray reflectivity distribution has been given, whichnamed XRR_DENmethod. According to the measured mass density, optical constant of thin film could be calculated. This is very important for evaluating the surfaceroughness PSD function of thin film sample from X-ray scattering distribution.3．The instrument was determined according to the analysis of the factors causingsystematic errors on the PSD function measurement. These factors include the effectsof the finite width of the detector slit, the width of the primary beam and the systemalignment error etc. Then the scattering indicatrix for different optical surfaces andthin film samples were measured, and one-dimensional PSD functions and effectiveRMS roughness were calculated by FOPT. Which coincide well with themeasurements of atomic force microscopy（AFM）。The results demonstrated thatFOPT is validity for measuring the surface roughness of supersmooth surface.Specifically, calculating optical constants from the experimentally measured massdensities by XRR_DENof the studied thin film samples could improve the measurementaccuracy.4．There presents an anomalous surface scattering （ASS） phenomenon during themeasurement of surface roughness of smooth surface. Experimental results indicatethat the anomalous scattering angle is various with the kind of materials used undercertain incidence wavelength and change slightly with the glancing angle and RMSsurface roughness. Moreover, all the measured anomalous scattering angles areslightly smaller than the critical angle values, and the measurement errors range from-8%to-0.3%。On the other hand, the anomalous surface scattering phenomenon ismore obviously as the increasing of grazing incidence angle and surface roughness.The reasons of anomalous surface scattering occurring have been analyzed. This is afoundation of future study about the anomalous surface scattering affect on the imagequality of grazing incidence image system.更多还原