折叠式激光投影光刻物镜的设计研究

针对大面积、高产量和节约型印制电路板(PCB)生产使用的激光投影光刻机,利用ZEMAX工程光学设计软件,对其投影系统进行了模拟设计与优化,并对优化后的结果进行了分析.对于设计的激光投影系统,其特征尺寸分辨力达到了9μm,全视场波像差小于λ/4,畸变小于0.000007%,这些指标符合实际要求.     

粗糙度对极紫外投影光刻掩模的影响

基于Nevot-Croce模型,计算了一系列具有粗糙界面的极紫外投影光刻掩模的反射光谱。通过拟合计算结果,得到了峰值反射率、带宽和中心波长与粗糙度的函数关系。根据光刻系统对照明均匀性的要求,讨论了在相同粗糙度变化范围内,分别由峰值反射率、带宽和中心波长引起的照明误差。结果表明,粗糙度对极紫外投影光刻掩模的峰值反射率影响最大。当掩模粗糙度为0.85±0.04nm时,峰值反射率将产生±0.9%的波动,并由此产生±1.5%的照明误差。为保证由峰值反射率导致的照明误差小于±1%,极紫外投影光刻掩模的粗糙度必须控制在±0.025nm以内。     

亚微米i线投影光刻物镜的光学设计与研制

叙述亚微米投影光刻物镜光学设计要点：光刻分辨力Ｒ与波长λ、数值孔径ＮＡ的关系；光学系统双远心的构成方法；光刻物镜的象差校正优化设计中的需控目标值等问题。介绍一个亚微米ｉ线投影光刻物镜的设计结果、光学制造公差和质量控制方法，以及其主要性能测试结果。     

数字光刻缩微投影系统物镜的设计

针对高精度数字光刻的缩微光学投影系统,提出并设计了一种适用于0.7XGA型数字微反射镜(DMD)的6片式数字光刻缩微投影物镜。通过优化和拼接三片式物镜结构,得到数值孔径NA=0.1,放大倍率为-0.2558,分辨力达3.5μm,不受DMD栅格效应影响且达到衍射极限的缩微物镜。经过Zemax软件模拟得到其全视场光程差小于λ/5,145cycles/mm处的调制传递函数(MTF)大于0.58,充分说明该缩微物镜已经达到光刻物镜设计要求。利用Monte Carlo分析方法,模拟加工装配了100组镜头,设定空间频率为145cycles/mm时,90%的镜头FMTF>0.55,验证了加工装配实际可行。     

球面投影光刻物镜的设计

针对人工晶体或隐形眼镜的面形上连续浮雕结构加工的特点,本文介绍了基于空间光调制器(DMD)曲面投影光刻物镜系统的设计方法.根据其成像面为曲面的特点,根据光学设计理论多次利用弯向物方的弯月形负透镜结构进行场曲校正,同时运用光的衍射原理优化设计物镜系统的数值孔径以消除DMD投影过程中的栅格效应. 运用ZEMAX工程光学设计软件对系统进行了模拟、优化,并对优化后的结果进行了分析.对于设计实例利用上述设计原则给出了设计结果,工作波长为g线(峰值波长λ=436nm),像面曲率r=22.5mm,视场φ6mm,数值孔径NA=0.1,分辨力为7.8 μm(64Ip/mm)时的光学调制传函值>0.8,畸变<±0.05%.     

光刻物镜高精度挠性结构镜框设计及分析

光刻投影物镜的透镜支撑形式决定透镜的面形精度,进而影响光学系统的成像质量。本设计为实现透镜面形精度优于5 nm的RMS值,提出一种三点挠性主支撑和六点弹片辅助支撑的支撑形式。综合考虑透镜自重、夹持力和热载荷对透镜面形影响,对支撑结构进行优化设计,并进行了仿真分析。仿真后的面形结果为：上表面面形PV 21.7 nm,RMS 4.49 nm;下表面面形PV 81.3 nm,RMS 3.63 nm。仿真结果显示：该种透镜的支撑结构可以满足光刻投影物镜的高精度面形指标要求。     

基于投影光刻技术的微透镜阵列加工方法

本文提出了一种基于投影光刻技术的微透镜阵列制备方法,成功制备多种口径、面形及表面粗糙度均良好的微透镜阵列。该方法采用0.2倍投影物镜,降低掩模板制造成本,实现不同口径微透镜阵列制备。采用掩模移动滤波技术,在降低掩模制备复杂性的同时,提高了微透镜阵列面形精度。本文对四种不同口径的微透镜阵列进行制备实验,分别为50 μm、100 μm、300 μm、500 μm,其表面形貌加工精度达到微米级,表面粗糙度达到纳米级。实验结果表明,该方法在微透镜阵列制造中具有很大的潜力,与传统方法相比,能够实现更低的线宽和更高的表面面形精度。

     

光刻物镜波像差绝对检测技术综述

光刻物镜是光刻机核心部件,其波像差大小决定着光刻机的分辨率和套刻精度。随着光刻机性能的逐步提升,光刻物镜波像差要求已经降低到0.5 nm (RMS)以下,这对波像差的检测是一个极大的挑战。现行的光刻物镜波像差检测方法 (如哈特曼法,剪切干涉法和点衍射法等)的检测精度往往受限于其系统误差,而绝对检测技术是一种能够将系统误差分离出来的技术,最终突破精度极限。本文回顾了光刻物镜系统波像差检测方法和波前绝对检测技术,详细梳理了绝对检测技术在不同波像差检测方法中的应用和研究进展,重点总结了绝对检测技术在不同波像差检测方法中的技术难点,同时结合这些难点,展望了光刻物镜波像差绝对检测技术的未来发展趋势。     

二元光学折/衍混合消色差望远物镜设计

首先从光栅衍射理论出发导出衍射光学元件的色散公式，并进一步推导出用一种材料进行折／衍混合消色差望远物镜设计的公式。最后给出全折射型、一个混合型消色差和一个改进型消色差望远物镜的例子，并进行了比较。结果说明，混合型透镜的性能优于全折射型透镜，而改进型消色差物镜的总体性能优于原混合消色差物镜     

基于成像球光强测量系统的光学设计

提出一种新的快速测量空间光强分布的方法,完成基于该方法测量系统的光学系统设计,并对光学系统的关键器件进行设计.利用Matlab编程和Solidworks三维建模得到自由曲面反射镜面型,Zemax光学软件设计优化得到双高斯物镜.光线追踪仿真软件LightTools对测量系统进行模拟仿真,验证系统的可行性,并对该构架下测量系统最小角分辨率和动态范围的关键性能指标进行分析.结果表明,设计的基于成像球的测量系统可实现空间光强分布测量.     

An ultrashort throw ratio projection lens design based on a catadioptric structure

In this paper, we present a rotational symmetry for an ultrashort throw (UST) lens with offset field. The UST lens has a throw ratio of 0.23 and a total track of 195 mm. The optical elements of the UST lens are comprised of two parts. First, a catadioptric projection lens where the catadioptric function permits reaching an ultrashort throw ratio, short total track, while at the same time requiring fewer lens elements. The second part is a collimating lens which takes advantage of the telecentric condition to generate uniform total internal reflection (TIR) in the TIR prism. With this design, an effective focal length of -1.96 mm and a f-number of 2.4 can be obtained. The root mean square spot size and lateral colour of all fields are smaller than one pixel in size. The maximum optical distortion of ?0.97% and TV distortion of 0.2% are acceptable. In terms of image quality, the modulation transfer function (MTF) values for all fields are above 0.65 at 0.245 line pairs/mm. Even when the tolerance error is considered, the MTF values for all fields are still above 0.3. The suitability of the novel UST lens design for projection applications is discussed.     

Wetting of Cell Aggregates on Microdisk Topography Structures Achieved by Maskless Optical Projection Lithography

Cell aggregates as a 3D culture model can effectively mimic the physiological processes such as embryonic development, immune response, and tissue renewal in vivo. Researches show that the topography of biomaterials plays an important role in regulating cell proliferation, adhesion, and differentiation. It is of great significance to understand how cell aggregates respond to surface topography. Herein, microdisk array structures with the optimized size are used to investigate the wetting of cell aggregates. Cell aggregates exhibit complete wetting with distinct wetting velocities on the microdisk array structures of different diameters. The wetting velocity of cell aggregates reaches a maximum of 293 µm h⁻¹ on microdisk structures with a diameter of 2 µm and is a minimum of 247 µm h⁻¹ on microdisk structures of 20 µm diameter, which suggests that the cell-substrates adhesion energy on the latter is smaller. Actin stress fibers, focal adhesions (FAs), and cell morphology are analyzed to reveal the mechanisms of variation of wetting velocity. Furthermore, it is demonstrated that cell aggregates adopt climb and detour wetting modes on small and large-sized microdisk structures, respectively. This work reveals the response of cell aggregates to micro-scale topography, providing guidance for better understanding of tissue infiltration.     

A freeform optics design with limited data for extended LED light sources

Abstract

This paper proposes an optimization method for designing a freeform lens which can produce a good uniform circular illumination distribution and obtain high efficiency on the target plane. The initial surface profile of the freeform lens is calculated based on the laws of reflection and the energy conservation law, and then is fitted using the non-uniform rational basis spline (NURBS) method. The control points and weights are applied to parameterize the shape of freeform lens. The merit function for the optimization is defined as relative standard deviation (RSD) of the simulated illumination from the desired illumination and the efficiency of the lens. The simulation results indicate that the RSD is shown to be lower than 0.157, and maximum efficiency can be as high as 83.9%. In addition, it is demonstrated that this algorithm can obtain high uniform illumination distribution on the target plane with less variables. Compared with the conventional method, the simulation results show that the modified algorithm converges with less variables, good uniformity and high efficiency. Moreover, a freeform lens with different lighting patterns and non-rotational symmetry can be produced by the proposed method.     

光学三维测量中结构光栅投影系统的开发

为解决结构光三维测量系统中的光栅投影质量问题,提出并实现了以物理光栅为核心的结构光栅投影系统。该系统以现代光栅制造技术制造的精密光栅元件为核心,基于幻灯投影原理实现高质量的光栅条纹投影,利用步进电机带动高精密滚轴丝杆进行平移实现投影光栅的切换。实验结果表明,基于该系统实现的光学三维测量系统的可以达到1：100以上的对比度,具有较大的光强和良好的景深,同时能获得连续的强度分布及较好的正弦性,测量误差小于0．04mm,测量精度约为0．03mm,满足工业应用的要求。     

极紫外光刻机工件台设计及仿真

作为极紫外光刻机的一个关键子系统，真空工件台的精度、速度、加速度、动态特性及同步性能对于光刻图形精度和光刻机的产率都起着重要作用．设计了一种适用于极紫外光刻机的真空工件台系统，该系统具有体积小、质量轻、精度高等特点．为了验证结构的合理性，还对工件台进行了结构仿真：包括静态仿真、瞬态仿真和模态仿真．仿真结果表明：结构设计合理，结构变形和固有频率均能满足光刻机的要求．     

A magnet system design for reduced gravity environment

Simulating a reduced gravity environment experienced in spaceships in a laboratory setting for studying different technical aspects (fluid transfer or propellant behavior, for example) is a primordial step prior to extraterrestrial explorations. We first present some results on boiling heat transfer in helium under reduced gravity using a commercial magnet and point out the limitations in volume and magnetic force homogeneity to perform reduced gravity experiments with such a non ad hoc magnet. Then, we present a new magnetic design to create a reduced gravity environment in large volume suitable for boiling test experiments in oxygen. Based on a modified design we present the magnetic configurations that allow compensating gravity for different elements such as hydrogen, water or helium but in smaller volumes. We detail the different aspects of winding techniques to achieve the requirements on magnetic force.     

Rational design of a diffractive homogenizer for a laser beam

The problem of designing a diffractive optical element (DOE) that produces a uniform-intensity beam from a spatially variable source is considered. Under the thin-lens approximation, the DOE is fully characterized by a phase function. Fresnel approximation is used to simplify the relationship between the input amplitude, the phase function, and the image intensity. The case where the light source has partial coherence is considered. A simple design procedure based on a lenslet array is proposed. It is shown that under certain physical assumptions, this `engineering' solution leads to an effective design capable of producing a uniform intensity from a time-varying, non-uniform source.