Fabrication of high precision X-ray mask for X-ray grating of X-ray Talbot interferometer

X-ray imaging is used in many applications such as medical diagnosis and non-destructive inspection, and has become an essential technologies in these areas. In one image technique, X-ray phase information is obtained using X-ray Talbot interferometer, for which X-ray diffraction gratings are required; however, the manufacture of fine, highly accurate, and high aspect ratio gratings is very difficult. X-ray lithography could be used to fabricate structures with high precision since it uses highly directive syncrotron radiation. Therefore, we decided to fabricate X-ray gratings using X-ray lithography technique. The accuracy of the fabricated structure depends largely on the accuracy of the X-ray mask used. In our research, we combined deep silicon dry etching technology with ultraviolet lithography in order to fabricate untapered and high precision X-ray masks containing rectangular patterns. We succeeded in fabricating an X-ray mask with a pitch of 5.3 μm. The thickness of the Au absorber was about 5 μm, and the effective area was 60  × 60 mm², which is a sufficient size for phase tomography imaging. We demonstrated the utility of the Si dry etching process for making high precision X-ray masks.     

Fabrication of large area diffraction grating using LIGA process

X-ray imaging is a very important technology in the fields of medical, biological, inspection, material science, etc. However, it is not enough to get the clear X-ray imaging with low absorbance. We have produced a diffraction gratings for obtaining high resolution X-ray phase imaging, such as X-ray Talbot interferometer. In this X-ray Talbot interferometer, diffraction gratings were required to have a fine, high accuracy, high aspect ratio structure. Then, we succeeded to fabricate a high aspect ratio diffraction grating with a pitch of 8 μm and small area using a deep X-ray lithography technique. We discuss that the diffraction gratings having a narrow pitch and an large effective area to obtain imaging size of practical use in medical application. If the pitch of diffraction gratings were narrow, it is expected high resolution imaging for X-ray Talbot interferometer. We succeeded and fabricated the diffraction grating with pitch of 5.3 μm, Au height of 28 μm and an effective area of 60 × 60 mm².     

双光栅干涉仪数字式位移传感器的研究

为了检定高准确度位移传感器、几何量计量定位、微细加工测量,同时,也测量那些可以转换为微位移或光程差的其它物理量。基于双光栅干涉仪原理,设计了一种数字式位移传感器,对该装置进行了理论分析和计算机模拟,实验验证:该测量装置的绝对误差不大于0.019μm。     

X-射线衍射物相分析的统计学方法

应用社会科学统计分析程序(SPSS)对X-射线衍射实验数据进行因子分析和聚类分析计算。结果表明在确定混合物中物相数目的同时,能够分离出每一物相的独立衍射线,为混合物的X-射线衍射物相定性分析提供了可靠的依据。     

X-射线衍射物相分析的统计学方法

应用社会科学统计分析程序（SPSS）对X-射线衍射实验数据进行因子分析和聚类分析计算。结果表明在确定混合物中物相数目的同时，能够分离出每一物相的独立衍射线，为混合物的X-射线衍射物相定性分析提供了可靠的依据。     

Fabrication of X-rays mask with carbon membrane for diffraction gratings

We have produced diffraction gratings for obtaining high resolution X-ray phase imaging, such as X-ray Talbot interferometer. These diffraction gratings were required to have a fine, high accuracy, high aspect ratio structure. Therefore, we decided to use the X-rays lithography technique that used synchrotron radiation of the directivity for a manufacture process. The accuracy of the completed structure depends largely on the accuracy of the X-ray mask. In our group, a resin material is conventionally used for the membrane of large X-ray masks. However, X-ray masks comprising a resin membrane have the disadvantage that, after several cycles of X-ray exposure, they crease and sag due to X-ray-derived heat. As a substitute for the conventional resin membrane, we experimentally fabricated a new X-ray mask using a carbon wafer membrane. The newly fabricated X-ray mask was subjected to X-ray exposure experiment. We succeeded in making the structure body which was almost shape. And the experimental results verified that the new mask did not deteriorate even when used repeatedly, demonstrating that it was highly durable.     

激光衍射光栅测试仪的设计与实现

激光二极管衍射光栅光斑亮度比和透过率的测定是影响VCD、DVD等设备中激光读写头以及光学镜头质量的关键因素.本设计采用高性能单片机AVR Atmegal6L设计并实现了650nm激光衍射光栅测试仪,对衍射光栅0级和1级光斑亮度比和光栅透过率测试误差小于2%,方差小于2.2×10-3,满足了光栅测试的精度和稳定性要求.     

3D deep X-ray lithography for producing a multi-channel Fourier transform interferometer

We introduce a modified LIGA process architecture to manufacture a static lamellar grating Fourier-transform spectrometer invented by Moser and Möller (European patent EP 0 765 488 B1, 1994). Such spectrometers hold unique advantages over common Michelson-type FTIRs including high time resolution, speed, compactness, and robustness. To cope with the spectrometer’s demand for precise high-aspect-ratio micro-fabrication, we present a modified LIGA process which enhances the X-ray lithography by means of a moving mask technique (Heussler and Moser Lithography method and apparatus PCT/SG2011/000376, 2011). The technique relies on independently moving multiple masks stacked on top of each other during the lithographic step and thus allows to locally vary the deposited dose in a positive tone photoresist. First manufacturing results as well as a performance test of a prototype spectrometer are reported.     

Fabrication of sub-micron structures for MEMS using deep X-ray lithography

Fabrication techniques of microstructures with high resolution and high aspect ratio are necessary for practical microelectromechanical systems (MEMS) that have high performance and integration. In order to fabricate microstructures with sub-micron resolution and high aspect ratio, deep X-ray lithography has been investigated using the compact synchrotron radiation (SR) light source called “AURORA”. An X-ray mask for sub-micron deep X-ray lithography, which is composed of 1 μm thick Au as absorbers, 2 μm thick SiC as a membrane and 625 μm thick Si as a frame, was designed. In preliminary experiments, the following results were achieved: EB resist microstructures with an aspect ratio of 22 corresponding with 0.07 μm width and 1.3 μm height were formed; a 10 μm thick PMMA resist containing no warp was formed by direct polymerization, enabling more precise gap control.     

Plane wave diffraction by circular transmission grating; finite-difference approach

Transmission gratings with circular elemental cross section are analyzed for diffraction of plane electromagnetic waves incident at oblique angles of incidence. The new solution method which is based on the finite-difference scheme is simple in nature and involves no unchecked approximation. Numerical results are obtained for various gratings at arbitrary angles of incidence. These results favorably compare with a number of similar data available in the literature. They further reveal some of the important properties of the transmission gratings. The proposed solution technique is also applicable to problems involving finite conductivity, and, therefore, should be of considerable interest to engineers and physicists.     

Fabrication of X-ray imaging zone plates by e-beam and X-ray lithography

X-ray imaging and microscopy techniques have been developed in worldwide due to their capabilities of large penetration power and high spatial resolution. Fresnel zone plates is considered to be one of the most convenient optic devices for X-ray imaging and microscopy system. The zone plates with aspect ratio of 7 and 13 have been fabricated by e-beam lithography combined with X-ray lithography in this paper. Firstly, the X-ray lithography mask of zone plates with outermost zone width of 100 nm was fabricated by e-beam lithography and gold electroplating techniques. Secondly, the zone plates with gold profile thickness of 700 and 1,300 nm were replicated by X-ray lithography and gold electroplating techniques. X-ray imaging and microscopy techniques were introduced to characterize the high-aspect-ratio zone plates’ inner structures. At the X-ray energy of 7.5 keV, the first-order focusing efficiency of zone plates with gold profile thickness of 700 nm is about 8.63%.     

Manufacture of diffraction grating on tiny parts by means of ultraprecision milling

The study deals with the manufacture of diffraction grating by applying the ultraprecision microgrooving technology. Microgrooving is performed by the use of a lathe-type ultraprecision milling machine having 1 nm positioning accuracy, together with a rotating diamond cutter. As an example of microgroove, a diffraction grating with 32 768 V-shaped grooves is fabricated in a pitch of 1 μm and a depth of 0.5 μm around the circumference of copper disk of 12 mm in diameter. The high-speed rotating cutter allows the microgrooves to be sharply machined without burrs and accumulative pitch errors, taking account of cutting order. The surface roughness of machined grooves is 1 nm (Ra), which experimentally shows good optical properties. Received: 21 December 1998 / Accepted: 18 January 1999     

中国微米纳米技术学会：高分辨X射线衍射元件的研制

X射线波带片是纳米X射线成像系统的核心元件之一,为了研制高分辨率X射线波带片,对纳米结构的电子束光刻和高精度电镀进行了实验研究。首先,通过对电子束曝光工艺版图进行优化设计,平衡了邻近效应对纳米结构的影响,有效地控制了光刻胶的扭曲和坍塌。实验结果表明,采用校正的工艺版图,用线曝光方式在800pC/c m2剂量下可以研制出厚度为270nm、最外环宽度为50nm的高分辨率X射线波带片光刻胶结构。然后,在配制的柠檬酸金钾电镀液中,优化了电镀工艺参数。采用金含量为10%的柠檬酸金钾电镀液,各电镀参数PH值为4.2,电镀温度为50℃,电流密度为0.2A/dm2电镀出高分辨率X射线波带片。     

Fabrication of ceramic microcomponents using deep X-ray lithography

In the last years the fabrication of micro components made from ceramic materials became more and more evident with respect to the pronounced chemical stability and the outstanding thermomechanical properties in comparison to plastics and metals. The aim of this work is the lithographic generation of ceramic microstructures avoiding an intermediate molding step using SU8 as pronounced sensitive resist matrix filled with fine ceramic powder in the submicron range. Focus of the research was to investigate the composite formation, patterning by x-ray lithography, developing, debinding and sintering to form stable ceramic parts. The addition of fine ceramic particles to low viscous liquids like SU8-10 leads to an increase of the viscosity. For a successful debinding and sintering a volume content of at least 40% ceramic is required resulting in a change of the viscosity from around 2 Pas up to a value of 1000 Pas at 25 °C and low shear rates. A modified casting procedure was developed for the formation of uniform resist films with a thickness around 300 m. Optimized exposure and development parameters allow the fabrication of good quality resist structures that can be further transformed into ceramic structures by sintering. Details of the work and results will be presented and discussed in this paper.At this point the authors would like to thank all people who supported this work.     

粉末X-射线衍射谱图的计算机物相分析

由国内自主开发,以X-射线衍射标准数据库为基础,比较完善及可靠的计算机物相分析系统仍不多见,随着我国加入WTO,开发一套拥有自主知识产权的识别系统变得十分重要。本程序以ICDD(国际晶体粉末衍射中心)的PDF2文件(粉末衍射文件)作为标准数据库,以Microsoft Visual C++ 6.0为开发工具,程序为Windows界面,采用向导式设计,具有谱图显示功能,改变了以往同类程序DOS界面不友好、速度慢、匹配不够准确及其它诸多缺点,并且多处使用人机对话方式,用户既可以让程序自动识别又可以根据经验,人工参与来提高识别准确度。本程序主要采用3,6,9强峰匹配筛选,元素及全谱图对照等手段。经程序计算与识别后,会将所有匹配上的记录以列表及谱图形式列出以供使用者参考,并且引入兼容性概念,将最终匹配上的记录加以组合,以确定物相组成,并且进行评分及计算各组分的粗略百分比组成,最终组合出结果,以谱图形式列出。它具有速度快、匹配准确等优点,能明确指出样品的物相构成。     

粉末X-射线衍射谱图的计算机物相分析

由国内自主开发，以X-射线衍射标准数据库为基础，比较完善及可靠的计算机物相分析系统仍不多见，随着我国加入WTO，开发一套拥有自主智产权的识别系统变得十分重要。本程序以ICDD（国际晶体粉末衍射中心）的PDF2文件（粉末衍射文件）作为标准数据库，以Microsoft Visual C 6.0为开发工具，程序为Windows界面，采用向导式设计，具有谱图显示功能，改变了以往同类程序DOS界面不友好、速度慢、匹配不够准确及其它诸多缺点，并且多处使用人机对话方式，用户既可以让程序自动识别又可以根据经验，人工参与来提高识别准确度。本程序主要采用3，6，9强峰匹配筛选，元素及全谱图对照等手段。经程序计算与识别后，会将所有匹配上的记录以列表及谱图形式列出以供使用者参考，并且引入兼容性概念，将最终匹配上的记录加以组合，以确定物相组成，并且进行评分及计算各组分的粗略百分比组成，最终组合出结果，以谱图形列出。它具有速度快、匹配准确等优点，能明确指出样品的物相构成。     

水溶液衍射实验的数据处理及解析

用θ-θ型X射线衍射仪测定323 K Na2SO4·20H2O溶液.叙述用Origin和KURVLR程序处理散射数据,获取溶液结构函数和径向分布函数的方法和步骤.用Gaussian多峰拟合法去卷积径向分布函数曲线上的弥散峰,拟合曲线与实验曲线吻合,其结果可解析径向分布函数.根据Na2SO4晶体结构和文献报道的水分子、Na+和SO42-水合结构确定曲线上各散射峰对应的作用项.     

Fabrication and performance of 2-D compound X-ray refractive lenses

Due to the weak refraction of X-rays in matter, a focusing or deflection of X-ray using conventional refractive optics was not feasible. However, since compound X-ray refractive lens (CXRL) with consecutive holes array was proposed, it becomes currently a noticeable issue in X-ray optics. In this paper, we report on fabrication and performance test of two types of PMMA (polymethyl methacrylate) CXRLs. Firstly, one dimensional refractive X-ray lenses of parabolic and circular shape is fabricated by LIGA process. Based on the results, we conduct a fabrication of 2-D CXRLs. Here we suggest a LIGA-self align method which doesn’t need a special align equipment and is simpler method than conventional one. Through performance tests, we show experimentally that CXRLs are novel optical components for the hard X-ray range of about 8 keV and that they have possibilities to apply the X-ray optics for micro-focusing, imaging, and lithography.     

Studying fabrication errors of the diffraction grating on the end face of a silver-halide fiber

A technology for fabricating a diffractive microrelief on an end face of a polycrystalline IR fiber (PIR-fiber) is studied. We discuss how fabrication imperfections of a beam-splitter implemented on the fiber’s output end face could affect the specified intensity distribution of diffraction orders. Recommendations for improving the characteristics of the microrelief to manufacture are worked out.     

Fabrication of electrostatic MEMS microactuator based on X-ray lithography with Pb-based X-ray mask and dry-film-transfer-to-PCB process

Lithographie Galvanoformung Abformung (LIGA) is a promising approach for fabrication of high aspect ratio 3D microactuator for dual-stage slider in hard disk drive. However, this approach involves practically challenging X-ray lithography and structural transfer processes. In this work, electrostatic MEMS actuator is developed based on a LIGA approach with cost-effective X-ray lithography and dry-film-transfer-to-PCB process. X-ray lithography is performed with X-ray mask based on lift-off sputtered Pb film on mylar substrate and photoresist application using casting-polishing method. High quality and high aspect ratio SU8 microstructures with inverted microactuator pattern have been achieved with the interdigit spacing of ~5 μm, vertical sidewall and a high aspect ratio of 29 by X-ray lithography using the low-cost Pb based X-ray mask. A new dry-film-transfer-to-PCB is employed by using low-cost dry film photoresist to transfer electroplated nickel from surface-treated chromium-coated glass substrate to printed circuit board (PCB) substrate. The dry film is subsequently released everywhere except anchor contacts of the electrostatic actuator structure. The fabricated actuator exhibits good actuation performance with high displacement at moderate operating voltage and suitably high resonance frequency. Therefore, the proposed fabrication process is a promising alternative to realize low-cost MEMS microactuator for industrial applications.