Fabrication of x-ray masks on a thick substrate for deep x-ray lithography

We consider a technique for manufacturing LIGA x-ray masks based on direct formation of a deep pattern topology of the mask by an x-ray microbeam. This technique does not require an intermediate mask, which strongly simplifies manufacturing and reduces the laboriousness and cost of the LIGA masks created. The basic processing steps (substrate pretreatment, resist coating, exposure, resist development, and galvanic process), advantages, and disadvantages of these x-ray masks are described. Examples of the created prototypes of copper LIGA masks on glassy carbon substrates and substrate-free self-supporting masks are presented.     

Focusing high-energy x-rays by a PMMA compound x-ray lens on Beijing synchrotron radiation facility

The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.     

Fabrication of a 256-bits organic memory by soft x-ray lithography

This paper reports a procedure of soft x-ray lithography for the fabrication of organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writing technology to lithograph positive resist, polymethyl methacrylate on the polyimide film. Then Au is electroplated on the polyimide film. Hard contact mode exposure is used in x-ray lithography to transfer the graph from the mask to the wafer. The 256-bits organic memory is achieved with the critical dimension of 250~nm.     

连续型平面衍射聚光透镜掩模的制作

针对目前二元光学元件掩模制作工艺过程的诸多不足，对连续型平面衍射聚光透镜掩模的激光直写制作工艺进行了研究。基于基尔霍夫标量衍射理论，采用光线追迹法设计了连续型平面衍射聚光透镜掩模。采用激光直写技术，利用CLWS 300M／C极坐标激光直写设备、S1830光刻胶和MICROPOSIT 351显影液，进行了刻写实验。实验表明，激光能量、预烘烤温度、显影液浓度以及预曝光对掩模微结构的制作均有影响。最后制作了掩模。与二元光学元件掩模的制作工艺相比，该技术具有工艺简单、制作周期短且易于操作的优点。     

Features of the manufacture of deep X-ray lithography masks in the siberian synchrotron and terahertz radiation center

The development of a low-cost technology to manufacture high-contrast X-ray LIGA masks is topical because this technology is important for various applied research on microstructured products with minimum element sizes of 10–50 μm, such as microfluid analytical systems, selective waveguide mesh-based elements to control terahertz (THz) radiation, microshaped optical elements for the visible range, etc. Technological particularities of mask manufacture are considered. A method to check the quality of masks is presented. Test microproducts manufactured using the produced deep X-ray lithography masks are demonstrated.     

LIGA technology for the synthesis of diffractive refractive intraocular lenses

The manufacturing of test diffractive refractive intraocular lenses is illustrated by means of LIGA (deep X-ray LIthography and GAlvanoplastics and polymer forming). Dynamic X-ray lithography used while rotating the substrate versus an X-ray mask fixed in a beam of synchrotron radiation (SR) yields smooth optical 3D surfaces with roughnesses of 10–30 nm rms in polymethylmethacrylate (PMMA) layers. The axisymmetric diffractive refractive profile of a lens is predetermined by the radial angular function of the X-ray mask topology. The quality of the optical surface is reproduced for the nickel master form, which is electroplated onto a gold layer atop the PMMA relief. The optical quality also remains high for replicated lenses synthesized in this manner during silicon polymerization.     

Chemical Analysis of Patterned Mask Cleaning in Organic Light Emitting Diode Fabrication with Raman Spectroscopy

Abstract

Despite the continually improving efficiency of the fabrication process used to manufacture the organic light emitting diode (OLED) emitter layer, which uses a shadow mask, a method for the cleaning and recycling of the shadow mask is still lacking. One of the main reasons for this is the absence of a quantitative/qualitative method to analyze the cleaning solution using simple in situ measurements. Recently, Raman analysis has become popular because of its convenience, ease of use, and suitability for in situ measurements. Thus, Raman spectroscopy has the capacity to analyze the solution used for cleaning shadow masks. A particular advantage of this approach is that it can detect organic contaminants in the cleaning solution, which are caused by the residue that remains on the shadow mask after the OLED emitter layer fabrication process. Raman spectroscopy has an advantage for analyzing solution condition and contaminant detection between the cleaning solution and organic chemical by using the Raman peak and fluorescence integration method.     

自集成透镜InGaAsP／InPDHLED及其离子束铣技术

本文报道在国内首次采用离子束铣技术研制自集成透镜InGaAsP/InP DH LED的实验结果。采用烘烤正性光致抗蚀剂来形成球状掩膜适合于离子束铣,且重复性很好。为了获得光洁的刻蚀表面,刻蚀条件均已最优化。     

Fabrication of high quality two-dimensional photonic crystal mask layer patterns

This work discusses the fabrication of two-dimensional photonic crystal mask layer patterns. Photonic crystal patterns having holes with smooth and straight sidewalls are achieved by optimizing electron beam exposure doses during electron beam lithography process. Thereafter, to precisely transfer the patterns from the beam resist to the SiO₂ mask layer, we developed a pulse-time etching method and optimize various reaction ion etching conditions. Results show that we can obtain high quality two-dimensional photonic crystal mask layer patterns.     

Vertical-cavity surface-emitting laser fabricated by two implantations using tungsten wires as mask

The design and fabrication of a room-temperature continuous wave (cw) vertical-cavity surface-emitting laser is reported. The device was fabricated by two deep H⁺ implantations using parallel tungsten wires as the resist mask. The direction of the mask in the first implantation is perpendicular to that in the second. The fabrication process is the simplest ever reported for vertical-cavity surface-emitting laser fabrication. A lowest threshold current of 17 mA and a maximum light output power of 4 mW were obtained.     

一种新颖的取样光纤光栅振幅版的研制

提出了一种新颖的用于制作取样光纤光栅的取样振幅版的设计方案，其特点是具有渐变的取样周期和不变的占空比，利用这种振幅版可以简单灵活地制作出反射峰波长间隔不同的取样光栅梳状滤波器，有利于提高取样光栅的制作灵活性并降低成本.对这种方法可能存在的不足也进行了分析.利用制作出的取样光栅，基于全光纤结构实现了具有游标尺式波长调谐机理的可选波长光纤激光器.     

Ultraviolet-Cured Polymer Micro-Optical Elements

A new fabrication method for polymer micro-optical elements is described which uses the contracting effect of photopolymers during the process of polymerization. Convex and concave microlens arrays and phase gratings were formed by irradiating a ultraviolet (UV)-curable monomer with incoherent UV light through an appropriate metallic mask. The morphological and optical characterization of the fabricated elements reveals that the surface profile of the elements depends on the pattern and aperture size of the mask employed.     

一种新颖的取样光纤光栅振幅版的研制

提出了一种新颖的用于制作取样光纤光栅的取样振幅版的设计方案,其特点是具有渐变的取样周期和不变的占空比,利用这种振幅版可以简单灵活地制作出反射峰波长间隔不同的取样光栅梳状滤波器,有利于提高取样光栅的制作灵活性并降低成本.对这种方法可能存在的不足也进行了分析.利用制作出的取样光栅,基于全光纤结构实现了具有游标尺式波长调谐机理的可选波长光纤激光器. 关键词： 取样光纤光栅 梳状滤波器 可选波长光纤激光器 振幅版     

Zone-doubling technique to produce ultrahigh-resolution x-ray optics

A method for the fabrication of ultrahigh-resolution Fresnel zone plate lenses for x-ray microscopy is demonstrated. It is based on the deposition of a zone plate material (Ir) onto the sidewalls of a prepatterned template structure (Si) using an atomic layer deposition technique. This results in a doubling of the effective zone density, thus improving the achievable resolution of x-ray microscopes. Test structures with lines and spaces down to 15 nm were resolved in a scanning transmission x-ray microscope at 1 keV photon energy.     

Formation for Bass-Relief Microprofiles Based on an Analytic Formulation

A method of fast design and fabrication for bass-relief micro-profiles is developed by using an analytic formulation to determine the exposure distribution. Based on an equivalent exposure threshold model, the formulation is simplified for the case of bass-relief profile corresponding to the smaller exposure dose. The mask function for a microlens array is designed without iteration involved by the analytic formulation. The experiment is performed to validate the method, and the fabrication result is obtained with the profile error less than 30nm （rms）.     

掩模分形提高光刻边缘锐度的研究

针对电寻址空间光调制器制作灰度掩模过程中,精缩透镜的低通滤波特性导致灰度掩模边缘锐度下降的问题,提出了掩模分形技术。对一幅高频灰阶掩模图形,按固定的或可变的低频采样。低频掩模的每个周期中,只包含原掩模图形多个周期中的一个抽样。通过实时掩模技术,将多个低频掩模按顺序曝光,从而恢复出原高频掩模图形。制作二元光栅时,分形掩模技术可使透镜造成的高频能量相对损失由35、23％降低至6．09％,同时,可将部分低频能量搬迁至中高频,较好地改善了灰阶掩模图形的边缘锐度。分形掩模还可以变多灰阶复杂掩模为简单的二元掩模,简化掩模的设计与实现,同时消除屏幕刷新率对掩模制作的影响。     

彩色等效灰度掩模制作方法研究

提出了一种利用彩色等效灰度理论设计掩模的新方法——数据库法.通过选取不同RGB值组合成特定颜色,由彩色胶片输出仪输出这些颜色组成的彩色掩模,获得的彩色胶片掩模用来线性调制曝光量,从而实现二元光学元件台阶深度的线性化.给出了理论计算和16阶菲涅耳透镜的实验结果,证明了数据库方法设计掩模的可行性.该方法的提出为灰度扩展提供了新途径.     

激光干涉光刻法制作100 nm掩模

 介绍了一种利用激光干涉光刻技术得到特征图形,并通过离子束刻蚀将图形转移到铬层上,从而获得掩模的方法。针对掩模透光率以及对干涉图形对比度可能产生影响的两个参数分别进行了数值仿真,从而证明此方法的可行性和参数的优化选择。自搭干涉光刻实验系统,用257 nm的激光光源实现光刻,得到特征尺寸为100 nm的图形,再经过离子束刻蚀,最终得到周期200 nm、线宽100 nm的掩模。     

Fabrication of high-spatial-frequency gratings through computer-generated near-field holography

We demonstrate an innovative method for fabrication of high-spatial-frequency grating structures. This technique makes use of the near-field diffraction patterns from computer-generated phase holograms for lithographic fabrication of grating structures with periods that are one half that of the phase hologram mask. Linear, rectilinear, and circular gratings were fabricated with this technique. Experimental results from gratings with periods to 0.5 mum and feature sizes to ~0.2 mum are presented.