A simplified fabrication process of Fresnel zone plates with controlling proximity effect correction

Fresnel zone plates (FZPs) for soft X-ray microscopy with an energy range of 284 eV to 540 eV are designed and fabricated in a simple method. An adequate aspect ratio of the resist mold for electroplating was obtained by the proximity effect correction technology for an incident electron beam on a single thick layer resist. Without additional complicated reactive ion etching, a sufficient electro plating mold for nickel structures was fabricated. The overall fabrication procedures which involve a mix-and-match overlay technique for electron beam lithography and an optic exposure system that centers the membrane on the nanostructures, and hybrid silicon etching technology in junction with deep anisotropy and a KOH wet method in order to release the backside Si substrates of the Si3N4 membranes with no deformation of FZPs are introduced. High quality nanostructures with minimum outermost zone widths of 50 nm and diameters of 120 microm were fabricated with simplified fabrication process and with cost-effective.     

The fabrication of carbon nanostructures using electron beam resist pyrolysis and nanomachining processes for biosensing applications

We present a facile, yet versatile carbon nanofabrication method using electron beam lithography and resist pyrolysis. Various resist nanopatterns were fabricated using a negative electron beam resist, SAL-601, and they were then subjected to heat treatment in an inert atmosphere to obtain carbon nanopatterns. Suspended carbon nanostructures were fabricated by the wet-etching of an underlying sacrificial oxide layer. Free-standing carbon nanostructures, which contain 130?nm wide, 15?nm thick, and 4?μm long nanobridges, were fabricated by resist pyrolysis and nanomachining processes. Electron beam exposure dose effects on resist thickness and pattern widening were studied. The thickness of the carbon nanostructures was thinned down by etching with oxygen plasma. An electrical biosensor utilizing carbon nanostructures as a conducting channel was studied. Conductance modulations of the carbon device due to streptavidin-biotin binding and pH variations were observed.     

Charge dissipation in e-beam lithography with Novolak-based conducting polymer films

Charging of common resist materials during electron beam (e-beam) writing leads to deflection of the electron beam path, which can result in significant pattern displacement. Here we report a new conducting polymer to eliminate charging. A common approach is to place the conducting layer underneath the e-beam resist layer. Conductivity equal or greater than 10(-4)?S?cm(-1) has been reported to prevent pattern displacement. Some other properties such as a flat surface layer, chemical inertness and insolubility in both the top resist solvent and the developer are also necessary. The way to achieve all these properties consisted in synthesizing a conducting polymer inside an insulating polymer to form an interpenetrating polymer network (IPN) which could combine their properties. Novolak was used as the host polymer and terthiophene (3T) as the monomer to polymerize. Cu(ClO(4))(2) initiates simultaneously the oxidative polymerization of the 3T and its subsequent doping inside Novolak during the bake step in a one-step reaction. Solvent-resistant and homogeneous conducting films with smooth surfaces were achieved. The conductivity was of the order of 10(-2)?S?cm(-1). Patterning of the top resist was carried out without disturbing its lithographic performance.     

FT-IR study of a chemically amplified resist for X-ray lithography

Microelectronic devices for future applications demand lithographic performance that falls within the 0.10 microm region and below. Chemically amplified resists (CARs), such as the positive tone commercial UVIII resist, offer a substantial gain in sensitivity, resolution, and process efficiency in deep ultraviolet, e-beam, and X-ray lithographies. In this work, the UVIII resist is characterized for X-ray lithographic applications by studying the "deprotection" or acid generation-diffusion process of the resist under different conditions of post-exposure bake (PEB) temperature and time, and of X-ray exposure dose. The X-ray irradiation from a copper anode at a wavelength of 1.33 nm was at an intensity of 30 microW/cm2 on the resist surface. The deprotection process of the resist during PEB was accurately monitored by using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 1151, 1369, and 2977 cm(-1) in the spectrum of the UVIII resist were found to be useful indicators for the completion of deprotection. Results of the experiments showed that the performance of UVIII could be optimized at the PEB temperature of 140 degrees C, a time of 2 min, and X-ray exposure dose of 12 mJ/cm2. The change in resist thickness after PEB was also measured. The results were confirmed by scanning electron microscopy (SEM) in which a test structure as small as 0.12 microm was obtained in a 1-microm-thick UVIII resist layer.     

Application of auxiliary metal layers to e-beam and X-ray lithography

Micron and sub-micron gold lines have been produced by liftoff following e-beam and X-ray exposures of resist coated chromium layers on silicon. Etching a 0.1 micron chromium layer after development results in an undercut which aids the liftoff process. This approach has been used in e-beam lithography on PMMA (i.e. positive resist) to decouple the e-beam exposure from generation of the undercut. In this way 0.7 micron gold lines separated by less than 0.3 microns have been produced. A similar approach when used in X-ray lithography on OEBR (negative resist) yielded gold lines down to 0.3 microns in width and separation. Scanning electron micrographs of patterns at various stages of processing are presented and the profiles of the resist walls and the nature of the undercut are described.     

医用诊断X射线半价层的测量

介绍了医用诊断X射线半价层测量的原理与曲线拟合法、平均值法、内插法、作图法等四种测量方法,结合实验数据分析了平均值法、内插法和拟合法的特点。医用诊断X射线束通常为“宽束”,曲线拟合法测量半价层需考虑积累因子的影响,通过调整吸收片厚度能快速计算出半价层;平均值法对于宽束X射线在较大的吸收片厚度范围内多次测量不能减小误差;内插法测量时内插间距的选择直接影响测量结果;采用平均值法和内插法时,所选吸收片厚度应使K/K0分布在1/2两侧。     

Rapid and Low‐Cost Prototyping of 3D Nanostructures with Multi‐Layer Hydrogen Silsesquioxane Scaffolds

A layer‐by‐layer (LBL) method can generate or approximate any three‐dimensional (3D) structure, and has been the approach for the manufacturing of complementary metal‐oxide‐semiconductor (CMOS) devices. However, its high cost precludes the fabrication of anything other than CMOS‐compatible devices, and general 3D nanostructures have been difficult to prototype in academia and small businesses, due to the lack of expensive facility and state‐of‐the‐art tools. It is proposed and demonstrated that a novel process that can rapidly fabricate high‐resolution three‐dimensional (3D) nanostructures at low cost, without requiring specialized equipment. An individual layer is realized through electron‐beam lithography patterning of hydrogen silsesquioxane (HSQ) resist, followed by planarization via spinning SU‐8 resist and etch‐back. A 4‐layer silicon inverse woodpile photonic crystal with a period of 650 nm and a 7‐layer HSQ scaffold with a period of 300 nm are demonstrated. This process provides a versatile and accessible solution to the fabrication of highly complex 3D nanostructures.     

氮化层弹性模量及残留内应力的测定

为了计算钢铁材料氮化层的弹性模量,提出了组合樑物理模型,采用等强樑的试样,测定氮化层弹性模量及残留内应力.试验结果表明:氮化层的弹性模量比母材高出约29.2%.X射线应力常数比母材提高44.4%.     

Proton microbeam irradiation effects on PtBA polymer

Proton beam lithography has made it possible to make various types of 3D-structures in polymers. Usually PMMA, SU-8, PS polymers have been used as resist materials for lithographic purpose. Microbeam irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 20 MeV proton microbeam are reported. Preliminary results on pattern formation on PtBA are carried out as a function of fluence. After writing the pattern, a thin layer of Ge is deposited. Distribution of Ge in pristine and ion beam patterned surface of PtBA polymer is studied using the optical and secondary electron microscopic experimental methods.     

应用于纳米制造的新型电子束抗蚀剂Calixarene的工艺研究

为了满足电子束光刻（EBL）对高分辨率、性能优秀抗蚀剂的需求,研究了将Calixarene衍生物作为电子束抗蚀剂在胶液配制、电子束曝光及显影等工艺过程中的相关技术.其中电子束曝光实验在JEOL JBX-5000LS系统上进行.实验结果表明,在入射电子能量50 keV、束流50 pA的条件下,Calixarene可以方便地形成50 nm的单线、50nm等线宽与间距的图形结构.通过与常用电子束抗蚀剂的对比,总结了Calixarene在电子束光刻性能上的优缺点,并分析了其成因.作为一种新型的高分辨率电子束光刻抗蚀剂,Calixarene有望应用在纳米结构制造、纳米尺寸器件及电路的研制等领域.     

Stamp design effect on 100 nm feature size for 8 inch NanoImprint lithography

Sub-100?nm resolution on a 200?mm silicon stamp has been hot embossed into commercial Sumitomo NEB 22 resist. A single pattern, exposed with electron beam lithography, has been considered to define the stamp and thus make it possible to point out the impact of stamp design on the printing. These results may be considered as a first attempt to define rules to solve the proximity printing effects (PPEs). Moreover, a large range of initial resist thickness, from 56 to 506?nm, has been spin coated to assess the effect of polymer flow properties for the stamp cavity filling and the printed defects. A?detailed analysis of the printed resist in dense hole patterns showed that the application volume conservation is enough to calculate the residual layer thickness as the height of the printed resist feature. Good accordance has been obtained between the theoretical approach and experimental results. Moreover, the impact of the pattern symmetry breakdown on mould deformation is clearly shown in this paper in the printed areas as well as in the unprinted areas.     

Proton beam writing of three-dimensional nanostructures in hydrogen silsesquioxane

Proton beam writing (p-beam writing) is a promising new direct-write lithographic technique for three-dimensional nanofabrication. In p-beam writing a megaelectronvolt proton beam is focused to a sub-100-nm spot size and scanned over a suitable resist material. Unlike electrons, when a proton beam interacts with resist it follows an almost straight path resulting in high aspect ratio structures with vertical, smooth sidewalls. The secondary electrons induced by the primary proton beam have low energy and therefore limited range, resulting in minimal proximity effects. Hydrogen silsesquioxane has been identified as a superior resist for p-beam writing, allowing the production of high-aspect-ratio structures down to 22 nm.     

Interferometric fabrication of modulated submicrometer gratings in photoresist

Interferometric recording is applied to the fabrication of modulated submicrometer gratings in photoresist.High diffraction efficiency requires optimized recording conditions, which are obtained by the use of an on-axis continuous surface-relief grating for the generation of the object beam. The optimized phase function is copied into the resist layer by means of a self-aligned two-step recording process with an intermediate copy in a volume photopolymer hologram. As a result, we demonstrate high carrier frequency surface-relief off-axis fan-out gratings for illumination in transmission with visible light.     

Investigation of the interfacial structure of ultra-thin platinum film deposited by cathodic–arc

Ultra-thin films are of interest in the production of X-ray mirrors that use a multilayer structure. The most commonly used deposition techniques are dc magnetron sputtering and electron beam evaporation; this paper presents results of cathodic–arc deposition. Ultra thin films of platinum with nominal thicknesses in the range 15–65 Å were deposited on silicon substrates and the film structure investigated using X-ray reflectivity and X-ray photoelectron spectroscopy. It has been found that the structure of the deposited films consists of three layers—the platinum film, a silicon oxide layer and a platinum silicide layer. In contrast to dc magnetron and electron beam deposited films, the silicide layer of cathodic–arc deposited films have a higher density and greater thickness, which is attributed to the higher energy process of this deposition technique. These attributes of the cathodic–arc deposited films suggest that the deposition technique is not suitable for production of mirrors of materials that react with each other, but for materials that do not the deposition technique is potentially more favourable than that of e-beam and magnetron sputtering.     

Study of a chemically amplified resist for X-ray lithography by Fourier transform infrared spectroscopy

Future applications of microelectromechanical systems (MEMS) require lithographic performance of very high aspect ratio. Chemically amplified resists (CARs) such as the negative tone commercial SU-8 provide critical advantages in sensitivity, resolution, and process efficiency in deep ultraviolet, electron-beam, and X-ray lithographies (XRLs), which result in a very high aspect ratio. In this investigation, an SU-8 resist was characterized and optimized for X-ray lithographic applications by studying the cross-linking process of the resist under different conditions of resist thickness and X-ray exposure dose. The exposure dose of soft X-ray (SXR) irradiation at the average weighted wavelength of 1.20 nm from a plasma focus device ranges from 100 to 1600 mJ/cm(2) on the resist surface. Resist thickness varies from 3.5 to 15 mum. The cross-linking process of the resist during post-exposure bake (PEB) was accurately monitored using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 862, 914, 972, and 1128 cm(-1) in the spectrum of the SU-8 resist were found to be useful indicators for the completion of cross-linking in the resist. Results of the experiments showed that the cross-linking of SU-8 was optimized at the exposure dose of 800 mJ/cm(2) for resist thicknesses of 3.5, 9.5, and 15 microm. PEB temperature was set at 95 degrees C and time at 3 min. The resist thickness was measured using interference patterns in the FT-IR spectra of the resist. Test structures with an aspect ratio 3:1 on 10 microm thick SU-8 resist film were obtained using scanning electron microscopy (SEM).     

IBAD合成CNx／NbN纳米多层膜

用离子束辅助沉积技术（ＩｏｎＢｅａＡｓｓｉｓｔｅｄＤｅｐｏｓｉｔｉｏｎ，ＩＢＡＤ）制成ＣＮｘ／ＮｂＮ纳米多层膜，研究了工艺参数（轰击能量，基片温度）对膜的结构和性能的影响，分析表明，多层膜内的ＮｂＮ为多晶结构，在轰击能量为４００ｅＶ，基片温度为６００℃时，得到了与β－Ｃ３Ｎ４的晶面间距相对应的三条电子衍射环，基片温度的上升，膜层的硬度上升，轰击能量增大，则膜层的硬度表现为先上升后下降，最大显微硬度     

Fabrication of phase masks with variable diffraction efficiency using HEBS glass technology

A new fabrication method of apodized diffractive optical elements is proposed. It relies on using high energy beam sensitive glass as a halftone mask for variable diffraction efficiency phase masks generation in a resist layer. The presented technology is especially effective in mass production. Although fabrication of an amplitude mask is required, it is then repeatedly used in a single shot projection photolithography, which is much simpler and less laborious than the direct variable-dose pattern writing. Three prototypes of apodized phase masks were manufactured and characterized. The main advantages as well as limitations of the proposed technology are discussed.     

Photochemical wet etching of silicon by synchrotron white X-ray radiation

We have investigated photochemical wet etching of n-type silicon (100) using synchrotron white X-ray radiation. During electroless photochemical wet etching under high flux white X-ray beam, the surface is electropolished. However, when the photon is reduced, the silicon surface becomes porous instead. The pore formation is greatly enhanced when an external potential is applied through a Pt counter electrode. The porous silicon layer exhibits strong photoluminescence signal.     

Non-vacuum laser deposition of buffer layers for coated conductors

A pulsed TEA-CO₂ laser in combination with the dynamic fluidized bed powder feeder was employed to deposit a thin CeO₂ buffer layer on the polycrystalline Ni-substrate in a non-vacuum environment. Use of the 30° powder jet inclination with respect to the laser beam axis along with the nano size precursor powder deposited a smooth layer on the entire surface of the substrate. Both EDS and X-ray diffractometry analyses were employed to confirm the stoichiometric nature of the deposited CeO₂ buffer layer.     

Polycarbonate-based ordered arrays of electrochemical nanoelectrodes obtained by e-beam lithography

Ordered arrays of nanoelectrodes for electrochemical use are prepared by electron beam lithography (EBL) using polycarbonate as a novel e-beam resist. The nanoelectrodes are fabricated by patterning arrays of holes in a thin film of polycarbonate spin-coated on a gold layer on Si/Si(3)N(4) substrate. Experimental parameters for the successful use of polycarbonate as high resolution EBL resist are optimized. The holes can be filled partially or completely by electrochemical deposition of gold. This enables the preparation of arrays of nanoelectrodes with different recession degree and geometrical characteristics. The polycarbonate is kept on-site and used as the insulator that separates the nanoelectrodes. The obtained nanoelectrode arrays (NEAs) exhibit steady state current controlled by pure radial diffusion in cyclic voltammetry for scan rates up to approximately 50 mV s( - 1). Electrochemical results showed satisfactory agreement between experimental voltammograms and suitable theoretical models. Finally, the peculiarities of NEAs versus ensembles of nanoelectrodes, obtained by membrane template synthesis, are critically evaluated.