数字灰度光刻成像物镜设计

为了研究数字灰度光刻成像系统中栅格效应对像质的影响.在成像系统优化参量已有的研究基础上,综合考虑工作效率、光刻准确度、加工制造成本等因素,设计了一种能够有效消除数字灰度光刻成像栅格效应的光刻物镜.此光刻物镜技术指标为,数值孔径NA＝0.3,工作波长λ＝442 nm,倍率10×,分辨率R≤1.2 μm,焦深4 μm,且镜片数量少,光学加工、光学校装公差要求低.结果表明,该镜头完全满足数字灰度光刻高质量成像的需要.     

用于数字光刻的非对称式投影物镜设计

针对DMD数字光刻,利用ZEMAX光学设计软件,设计出了一套适用于型号 0.7XGA DMD的10片式光刻投影物镜。该物镜采用非对称性结构,前组为改进的三分离物镜,后组为匹兹伐物镜加平像场镜,分辨率为2 m,近轴放大倍率为-0.15,像方数值孔径NA为0.158,全视场波像差小于/20 ,畸变小于0.014%,焦深为20 m,通过各项评价可知系统已经达到了衍射极限。在对该镜头进行公差分析后,利用Monte Carlo方法,模拟组装加工了100组镜头,得到90%的镜头MTF＞0.46,50%的镜头MTF＞0.51,证明了这种非对称性结构加工和校装的可能性。     

三波段光学成像系统设计及鬼像分析

为了对目标的多波段辐射特性进行测量,设计了一套300~1 000nm三波段光学成像系统.该系统共用同一入射窗口,采用两个直角棱镜进行分光,每个波段使用独立的光学成像镜头,能同时得到目标的紫外、可见光和近红外图像.利用LightTools软件对此系统的鬼像进行模拟分析,发现棱镜表面和窗口玻璃之间的光束多次反射之后,经过光学成像镜头聚焦到探测器靶面上,形成了目标的多重鬼像,大大降低了图像的对比度.实验结果表明:采用本文所述方案,三波段成像系统能达到较好的像质;将窗口玻璃和第一个棱镜的角度控制在7″之内可以消除鬼像,对使用棱镜作为分光元件的多波段光学成像系统的设计和研制具有一定的参考意义.     

基于ZEMAX的大视场投影镜头设计

针对大视场投影镜头的设计问题,利用ZEMAX光学设计软件,通过各种操作数对镜头的基本参数和外形尺寸进行限制,并利用镜头架构的方式进行优化及大视场投影镜头的设计。其主要光学参量为:焦距为13.6 mm,全视场角为60°,相对孔径为1/1.6。设计结果表明:镜头的最大畸变量绝对值小于3% ,最大场曲小于0.06 mm,全视场MTF值在空间频率50 lp/mm时高于0.6,基本达到衍射极限。该镜头由10片球面镜组成,光学系统结构紧凑、易加工。     

行星光学远程着陆模拟器光学系统设计

为了实现对行星光学远程着陆过程的光学模拟以及满足行星光学远程着陆系统导航算法的地面测试需求,提出了以商用投影仪显示系统为基础的模拟器光学系统方案,重点阐述了系统的光学设计思想,并给出了设计结果.首先,介绍了模拟器的工作原理和系统组成,在此基础上,由技术要求及所选择的投影仪和CCD参数确定了投影镜头和成像镜头的光学系统指标,最后给出了投影镜头、成像镜头及系统对接的光学结构图,像差曲线、点列图和MTF曲线图.仿真分析结果表明:系统的点列图中的弥散斑对称性都很好,有利于模拟器系统的后续图像处理和判读,同时系统在Nyquist频率(91 lp/mm)处的MTF设计值接近0.6,系统整体成像性能良好.设计结果可作为研制行星光学远程着陆模拟器系统的基础.     

相对孔径为1∶1镜头的光学系统设计

介绍一种相对孔径为1:1的光谱摄像镜头。利用非球面光学表面将复杂化的Petzval型结构形式改进为3片结构,其主要光学参数f′=120mm，F=1，τ≥90%，系统MTF=0.85时的成像质量所对应的空间频率大于20lp/mm。结合非球面加工工程化研究需要对该镜头的结构进行优化，给出了多种像差曲线及MTF数据，并对未来可进行的进一步改进进行了探讨。     

一种新型微透镜阵列成象式投影光刻系统的研究

从理论和实验两方面入手,系统地研究了微透镜阵列的形成原理和制作工艺,分析了微透镜阵列的面形结构,得到了联系微透镜阵列矢高与制作工艺参量的经验公式.并且将四片微透镜阵列耦合,形成一个深紫外光刻的1:1成象的多孔径微小光刻系统.从几何光学理论出发,分析了这个光刻系统综合成象的特点,讨论了这种光刻系统的光学性能,并给出了实验测量方法.     

基于CODE V和LightTools的成像系统初级鬼像分析

对鬼像的基本概念和形成原因进行了介绍与分析,提出了利用光学设计软件CODE V定性分析与光机适配性软件LightTools定量分析相结合的鬼像仿真分析方法。使用lightTools软件仿真与系统探测器归一化真实响应照度值相比较找出鬼像路径,给出改进措施。对验证实验中给定的电视成像光学镜头的鬼像路径进行计算和仿真,计算结果表明,镜头轴上鬼像路径的归一化响应照度为3.5×10-5,小于探测器的归一化响应范围9.85×10-5~1,探测器无响应,即不产生鬼像,证明该仿真分析方法正确可行。     

亚10 μm线宽的投影光刻物镜设计及其成像性能的实验测定

 采用Zemax软件设计出6镜片、数值孔径为0.06、2倍缩小、以405 nm半导体激光器为光源、分辨精度达5 μm、视场12 mm×12 mm 内波像差小于1/4波长、畸变小于0.005%的双远心投影光刻物镜的设计方法。将设计的物镜实物化,并对其光学传递函数(MTF)作精确的实验测定,利用所提出的MTF标准实验测量法,得到该投影物镜的成像性能达亚10 μm线宽。     

50 nm分辨力极端紫外光刻物镜光学性能研究

极端紫外光刻 (EUVL)作为实现 10 0～ 32nm特征尺寸微细加工的优选技术 ,其光刻物镜的光学性能是实现高分辨图形制作的关键。利用光学设计软件CODEV对 6枚非球面反射镜构成的光刻物镜设计和光学性能分析 ,其分辨力可以实现 5 0nm ,曝光面积为 2 6mm× 1mm。结果表明 ,光学性能对曝光场点的依赖关系。在全曝光场中进行了光学性能分析 ,其最大畸变为 3.77nm ,最大波面差为 0 .0 31λ(均方根值 ) ,该缩小投影物镜完全可以满足下一代极端紫外光刻机的性能要求     

Al(111)/Al_3Li(111)的界面性质

运用基于第一性原理的平面波贋势法,计算研究了Al (111)/Al_3Li (111)的界面性质.结果表明:Al (111)/Al_3Li (111)的界面具有三种原子配位关系结构,其中界面处仍保持与基体Al一致的三明治堆垛构型的界面稳定性最好.计算表明,该结构界面最薄弱层,位于Al_3Li (111)内,其分离功最小(约1.53 J/m~2),强度最弱,而基体Al和Al_3Li内部的强度随着到界面距离的增大而逐渐增强.     

锰原子的二步多光子与三步三光子共振电离研究

激光共振电离技术是痕量分析中的重要手段之一。文章以速率方程理论为基础,对锰原子的激光共振电离过程进行了分析,讨论了电离过程中各级激发光功率密度及激光作用时间对电离效率的影响;提出了根据所要求的电离效率和激光作用时间计算所需要的各激发光或电离激光的功率密度的方法;得到了饱和激发或饱和电离的规律及阈值条件。研究发现,在激光作用时间为10 ns时,锰原子饱和电离的激光强度阈值基本都在108 W·cm-2的量级,只有“1+1”双色双共振低三个量级;而“1+1”和“1+1+1”饱和激发的激光强度阈值则在102～103 W·cm-2量级;并且随着激光作用时间的增加,各过程的饱和激发和饱和电离的激光强度阈值将单调减少。     

Two-photon photoemission from Ni (1 1 0) and (1 1 1) surfaces

Photoemission was observed when the samples were irradiated with photons in the energy range from 2.5 to 3.3 eV from a tunable dye laser with an intensity of 10⁸Wcm^?2. The emission shows a quadratic intensity dependence. The variation with angle of incidence and polarization is different for the two surfaces. The result obtained from the (1 1 0) surface is discussed with help of the band structure as a two-photon surface photoelectric effect.     

Schottky barriers on diamond (1 1 1)

We have measured Schottky barrier heights Ø_B = 1.3 eV for Au and Ø_B = 1.5 eV for Al on (p-type) diamond(1 1 1)?(1 × 1) using photoelectron spectroscopy with synchroton radiation. These barrier heights yield a barrier index of S = 0.2, which is closer to the values for Si and Ge (S ～ 0.1) than to the value S = 0.4 calculated for jellium on an ideal diamond(1 1 1) surface. After reacting Al with the diamond surface by annealing to 800° C, we find that Ø_B decreases by 0.24 to 1.25 eV.     

Structure of the laser annealed Si(1 1 1)-(1 × 1) surface

LEED analysis of the laser annealed Si(1 1 1)-(1 × 1) surface shows that a model with a graphite-like top double layer of atoms with a spacing of 2.95±0.02 Å from the second double layer describes the LEED data as well as the Zehner model, but involves large displacements of the atoms normal to the surface as required by ion scattering results. It is suggested that this model provides a natural interpretation of the low energy He atom scattering data for the Si(1 1 1)-(7 × 7) surface.     

Comparing the band structure of Ag(1 1 1) monolayers on Ni(1 1 1) and Ni (0 0 1)

Ag(1 1 1) monolayers prepared on two substrates, Ni(1 1 1) and Ni(0 0 1), were studied with angle-resolved photoemission; their two-dimensional band dispersions were found to be identical within experimental uncertainties. Comparing the present results with those for Ag/Cu(0 0 1), the major difference is just a shift of 0.32 eV in all the binding energies. Thus the band topology of Ag overlayers in these systems is quite insensitive to the electronic and atomic structures of the substrates.     

InAs/GaAs (1 1 1)A heteroepitaxial systems

We studied the structural, electrical, and mechanical properties of an InAs thin film grown on GaAs (1 1 1)A substrates by molecular beam epitaxy. In contrast to conventionally used (0 0 1) surfaces, where Stranski–Krastanov growth dominates the highly mismatched heteroepitaxy, layer-by-layer growth of InAs can be established. One of the largest advantages of this unique heteroepitaxial system is that it provides a two-dimensional electron gas system in the near-surface region without the problem of electron depletion. We review the fundamental properties and applications of this unique heteroepitaxial system.     

Precise semiconductor nanotubes and nanoshells fabricated on (1 1 0) and (1 1 1) Si and GaAs

In our previous works, we showed that ultrathin epitaxial heterofilms (down to two monolayers for the case of InGaAs/GaAs) can be controllably detatched from substrates and rolled, under the action of internal stresses, into various cylindrical micro- and nanoshells (tubes, scrolls, rings, spirals, etc.). The present review outlines the cornerstone stages in the development of this fabrication technology for semiconductor and metal nanoobjects, including: (1) directional rolling of films yielding 3D micro- and nanoshells of various shapes; (2) assembling of micro- and nanoshells in more complex architectures; (3) super-critical drying of nanoshells, and (4) formation of nanoshells whose sizes can be precisely controlled in three dimensions.With this technology new possibilities that open up for the use of strained films, selectively, grown on uncommonly used (1 1 0) and (1 1 1) surfaces, are presented. The role of mechanical anisotropy in the formation of the 3D nanoshells and the electrical and mechanical properties of formed nanotubes are discussed.     

Hanle lifetime measurements of SrI 1P1 and CaI 1P1 levels excited by a neutral beam of 1 1S0 helium atoms

A 0.8 keV He(1 ¹S₀) beam was used to coherently excite the ¹P₁ levels of Sr and Ca targets. The coherence appears as an alignment of the excited state with respect to the beam axis. We report here the results of a Hanle measurement, or a zero-field level-crossing experiment, performed on these coherently excited levels. The radiative lifetimes of the SrI ¹P₁ and CaI ¹P₁ levels were measured to be 4.7 ns and 5.3 ns, respectively. These values are in good agreement with conventional Hanle measurements.