Fabrication of Silicon Crystal-Facet-Dependent Nanostructures by Electron-Beam Lithography

Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a （100）-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This technique takes advantage of the large difference in etching properties for different crystallographic planes in alkaline solution. The minimum size of the trapezoidal top for those Si nanostructures can be reduced to less than 10nm. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） observations indicate that the etched nanostructures have controllable shapes and smooth surfaces.

A New Method to Retrieve Proximity Effect Parameters in Electron-Beam Lithography

A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line is used as test pattern to determine proximity effect parameters and the normalization approach is adopted in experimental data transaction in order to eliminate the need of measuring exposure clearing dose of the resist.Furthermore,the parameters acquired by this method are successfully used for proximity effect correction in electron beam lithography on the same experimental conditions.

The Application of Electron-Beam Welding in Pellet Mold Preparation

This paper provides insight into the application of electron-beam welding in pellet mold preparation,highlighting the importance of the combination of electron-beam welding and pellet mold preparation in the fields of microstructure joining and micro-and nanostructure preparation.Precise material joining and microstructure fabrication can be achieved by the precise control of electron-beam welding and the shape adjustment of pellet molds.These applications hold significant potential in the modern industrial field,providing robust support for the development of new materials and the growth of the petrochemical industry.This paper asserts that in the future,the ongoing development of electron-beam welding and pelletizing template technology will unlock new possibilities in the field of petrochemicals,fostering progress in science and technology.

Electron-Beam Welding Joint Strength of Dissimilar Materials

This paper provides an in-depth discussion of the joint strength of electron beam welding of dissimilar materials.The effect of welding parameters and material properties on the joint strength was analyzed,and an argument for the optimal parameter combination is presented.Electron-beam welding technology offers several advantages,including high energy density and the ability to create fine weld seams.However,it also presents certain challenges,such as the complexity of welding parameters and the potential generation of brittle phases.The analysis conducted in this paper holds significant importance in enhancing the quality and efficiency of dissimilar material welding processes.

Causes and control of welding cracks in electron-beam-welded superalloy GH4169 joints

Welding joint of GH4169 alloy with a good formation was obtained. No macroscopic defects occurred in the joint. The weld had mainly a dendritic structure; the base metal was a solid solution of Ni, Cr, and Fe, and the strengthening-phase particles such as Ni3Nb were dispersively distributed along the grain boundary. The average tensile strength of the joint reached 743.7 MPa, and the Vickers hardness of the weld exceeded HV 300. Because of the segregation of the low-melting compound Ni3Nb at the grain boundary of the fusion zone, liquid cracks tended to occur as a result of welding stress. The formation of liquid cracks was inhibited by adding an alloying element, Mn, to the welding bath, because Mn diffused to the fusion zone and the high-melting phase Mn2Nb formed, and thus the overall properties of the joint were improved.

可低温固化正性光敏聚酰亚胺的制备与性能

随着重新布线层半导体封装技术的发展,对可低温固化的正性光敏材料的光刻性能、力学性能、热力学性能和耐化学性能的要求越来越高。为此,笔者研制了一种可低温固化的正性光敏聚酰亚胺(p-PSPI)材料。在溶剂N-甲基吡咯烷酮(NMP)中,将4,4′-氧双邻苯二甲酸酐与2,2′-双[3-(3-氨基苯甲酰胺)-4-羟基苯基]六氟丙烷、硅二胺(SiDA)和3-氨基苯酚通过聚合反应得到聚酰胺酸,再进行羧基的酯化得到聚酰胺酸酯(PAE),将PAE与感光剂重氮萘醌化合物、酚酯型热交联剂、偶联剂KBM-1403和亚胺化催化剂2,6-二甲基哌啶溶解于γ-丁内酯中进行复配,得到可低温固化的p-PSPI胶液。对p-PSPI进行水性碱性显影性能测试,在膜厚15μm条件下,光刻分辨率能够达到10μm;经200℃低温固化后,利用傅里叶变换红外光谱仪、动态热机械分析仪、热重分析仪等分析测试,结果表明,p-PSPI的亚胺化率达到98%以上,拉伸强度为108.4 MPa,断裂伸长率为10.35%,储能模量(150℃)为2.18 GPa,5%热失重温度达到367.69℃;经耐化学性能测试,p-PSPI对有机溶剂(NMP,二甲基亚砜和丙酮)、酸碱(30%HNO3,30%H2SO4,1%HF和5%KOH)以及氧化剂(10%H2O2)具有优良的耐化学稳定性,可满足低温固化条件下半导体封装所需的工艺条件。

Recent advances in lithographic fabrication of micro-/nanostructured polydimethylsiloxanes and their soft electronic applications

The intensive development of micro-/nanotechnologies offers a new route to construct sophisticated architectures of emerging soft electronics.Among the many classes of stretchable materials,micro-/nanostructured poly(dimethylsiloxane)(PDMS)has emerged as a vital building block based on its merits of flexibility,stretchability,simple processing,and,more importantly,high degrees of freedom of incorporation with other functional materials,including metals and semiconductors.The artificially designed geometries play important roles in achieving the desired mechanical and electrical performances of devices and thus show great potential for applications in the fields of stretchable displays,sensors and actuators as well as in health-monitoring device platforms.Meanwhile,novel lithographic methods to produce stretchable platforms with superb reliability have recently attracted research interest.The aim of this review is to comprehensively summarize the progress regarding micro-/nanostructured PDMS and their promising soft electronic applications.This review is concluded with a brief outlook and further research directions.

Electron-beam Treatment of Tungsten-free TiC/NiCr Cermet Ⅰ:Influence of Subsurface Layer Microstructure on Resistance to Wear during Cutting of Metals

An experimental investigation were performed on the effect of the impulse electron-beam irradiation upon microstruc-ture of the surface layer and on wear resistance of a cutting tool for sintered TiC/NiCr cermet. The results showed that the surface electron-beam treatment of the TiC/NiCr cermet is an efficient method for investigating the mi-crostructure and phase composition in the surface layer of the powder composite and there are optimal regimes of electron-beam treatment, which ensure a substantial increase in the resistance of the cermet to wear during cutting of metals.

Fabrication of Anti-reflecting Si Nano-structures with Low Aspect Ratio by Nano-sphere Lithography Technique

Nano-structured photon management is currently an interesting topic since it can enhance the optical absorption and reduce the surface reflection which will improve the performance of many kinds of optoelectronic devices, such as Si-based solar cells and light emitting diodes. Here, we report the fabrication of periodically nano-patterned Si structures by using polystyrene nano-sphere lithography technique. By changing the diameter of nano-spheres and the dry etching parameters, such as etching time and etching power, the morphologies of formed Si nano-structures can be well controlled as revealed by atomic force microscopy.A good broadband antireflection property has been achieved for the formed periodically nano-patterned Si structures though they have the low aspect ratio(<0.53). The reflection can be significantly reduced compared with that of flat Si substrate in a wavelength range from 400 nm to 1200 nm. The weighted mean reflection under the AM1.5 solar spectrum irradiation can be as low as 3.92% and the corresponding optical absorption is significantly improved, which indicates that the present Si periodic nano-structures can be used in Si-based thin film solar cells.

Electron-beam Treatment of Tungsten-free TiC/NiCr CermetⅡ: Structural Transformations in the Subsurface Layer

The character of structural changes in the surface layer of titanium carbide （TiC） with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The thermal influence of the electron-beam irradiation on the surface layer microstructure of the composite fine-grained material was mathematically analyzed. Quantitative estimations of the depth of the zone in microstructural phase transformations were carried out. The microstructure and concentration profile of Ti distribution in the metallic binder over the cross section of the surface layer with microstructural phase transformations after electron-pulse treatment of the hard metal surface were experimentally investigated.

Detection and processing of molten-pool image of electron-beam deep-penetration welding based on visual sensing

A visual sensing system was developed. The system is suitable for titanium-alloy electron-beam welding, and senses and detects molten-pool dynamic processes. A suite of processing programs for colored molten-pool images in titanium-alloy electron-beam welding was developed using Matlab software; molten-pool edge images are completely obtained using the program. The Matlab software was used to write a program which could extract the molten-pool width. The functional relationship between the molten-pool width and penetration under the experimental conditions was obtained by a curve-fitting method, and provided the theoretical basis for further penetration control.

Compact intense electron-beam accelerators based on high energy density liquid pulse forming lines

This paper provides a review of the compact intense electron-beam accelerators (IEBAs) based on liquid pulse forming lines (PFLs) that havebeen developed at the National University of Defense Technology (NUDT) in China. The history and roadmap of the compact IEBAs used todrive high-power microwave (HPM) devices at NUDT are reviewed. The properties of both de-ionized water and glycerin as energy storagemedia are presented. Research into the breakdown properties of liquid dielectrics and the desire to maximize energy storage have resulted in theinvention of several coaxial PFLs with different electromagnetic structures, which are detailed in this paper. These high energy density liquidPFLs have been used to increase the performance of IEBA subsystems, based on which the SPARK (Single Pulse Accelerator with spark gaps)and HEART (High Energy-density Accelerator with Repetitive Transformer) series of IEBAs were constructed. This paper also discusses howthese compact IEBAs have been used to drive typical HPM devices and concludes by summarizing the associated achievements and theconclusions that can be drawn from the results.

Investigations on the time evolution of the plasma density in argon electron-beam plasma at intermediate pressure

The time evolution of the argon electron-beam plasma at intermediate pressure and low electron beam intensily was presented.By applying the amplitude modulation with the frequency of 20 Hz on the stable beam current,the plasma evolution was studied.A Faraday cup was used for the measurement of the electron beam current and a single electrostatic probe was used for the measurement of the ion current.Experimental results indicated that the ion current was in phase with the electron beam current in the pressure range from 200 Pa to 3000 Pa and in the beam current range lower than 20 mA,the residual density increased approximately linearly with the maximum density in the log-log plot and the fitting coefficient was irrelative to the pressure.And then three kinds of kinetic models were developed and the simulated results given by the kinetic model,without the consideration of the excited atoms,mostly approached to the experimental results.This indicated that the effect of the excited atoms on the plasma density can be ignored at intermediate pressure and low electron beam current intensity,which can greatly simplify the kinetic model.In the end.the decrease of the plasma density when the beam current was suddenly off was studied based on the simplified model and it was found that the decease characteristic at intermediate pressure was approximate to the one at high pressure at low electron beam intensity,which was in good accordance with the experimental results.

“园·图”互印研究视角中的苏州古典园林构景研究

通过对苏州古典园林的实地调研,从景的内部结构入手,归纳出33种景的构成方式,并且总结了苏州古典园林的构景方法、构景的变化规律以及构景的思想根源。在研究方法上亦采用图像引证法,精心择取苏州古典园林的实景型版刻插图、在苏州刊刻的文学性版刻插图,即通过历时性与共时性的双重图像资料引证视角,将现实景观照片与园林版画共同运用于“构景法式”的图示指引作用说明。研究结果不仅为古典园林的研究提供新的思路,而且有助于在当代景观设计中继承传统和设计创新。

不同气压下毛细管放电三束等离子体发光功率

在给定毛细管结构参数和放电条件的情况下,计算了毛细管放电三束等离子体的发光功率,并在毛细管放电三束等离子体极紫外光刻光源演示装置上进行了实测,测量数据与理论值基本相符。结果表明:三束等离子体发光的过程中,由于不同氮气气压下的光谱吸收和光学屏蔽极大削弱了极紫外光的输出能量,导致毛细管放电三束等离子体的发光功率随氮气气压的变化表现出特有的规律;与毛细管放电单束等离子体相比,极大输出对应的最佳气压明显提高。

浅议“工程创新战略”

工程创新战略在建设创新型国家的背景下非常重要。文章首先通过案例讨论了工程哲学引发了对工程创新关注;之后从“双碳”目标、科技基础设施建设、集成电路产业、光刻机技术等方面讨论了工程创新的源起和国家战略的落地。工程创新是实现高质量发展的必由之路,需要解决国家在科技进步和经济增长进程中所遇到的难点和阻碍。只有通过工程创新才能解决碳中和、推动经济高质量发展等国家战略问题。

高数值孔径投影光刻物镜的光学设计

针对45nm节点投影光刻物镜的应用,开展了工作波长为193nm的深紫外浸没式高数值孔径（NA）投影光刻物镜的研究和研制。设计了数值孔径（NA）为1.30的离轴三反射镜投影光刻物镜和NA为1.35的同轴两反射镜投影光刻物镜,并对两个设计方案的优劣进行对比分析,选择了同轴式结构作为最终的设计方案。分析了系统在不同NA情况下可变光阑与其远心度之间的关系,提出了用双可变曲面光阑的设计方案来优化系统的远心度。实验表明,应用本文设计方案,光刻物镜的波像差小于1nm,畸变小于1nm;新型的可变光阑使系统NA在0.85～1.35变化时的最大远心度由5.83～17.57mrad降低至0.26～3.21mrad。本文提出的设计方案为45nm节点高数值孔径投影光刻物镜的研制提供了有益的理论依据和指导。

利用软模板和紫外光固化技术制备超疏水表面

研究了一种制备超疏水表面的新方法.该方法以复制了荷叶表面结构的聚二甲基硅氧烷(PDMS)弹性体为软模板.利用可紫外光交联预聚物在模板压印条件下固化成型,得到了具有微乳突结构的仿荷叶表面.制备的仿荷叶表面表现出了超疏水性能.通过对紫外光固化体系中的单体含量、交联剂含量、引发剂含量、以及紫外曝光时间等因素的研究,得到了使仿荷叶表面的疏水性优化的条件.

古钾盐成矿条件和塔里木盆地找钾研究

我国已发现的钾盐矿床不能满足国民经济发展的需求,寻找新的大型钾盐矿床是一项紧迫的任务,塔里木盆地西部,在地史时期接受多次海侵,且盆地内广泛出露岩盐矿,是一有利的成矿区。古盐湖演化的最后阶段,浓度程度高的卤水汇聚到盆地的次级拗陷中,最后形成钾盐矿床,所以确定盐湖演化阶段盆地的次级拗陷位置对寻找钾盐矿至关重要。在详细查阅和消化前人资料的基础上,结合最近的野外考察认识和室内样品分析的数据,确立库车盆地的拜城—轮台地区和莎车盆地的喀什—和田、乌恰—阿克陶地区为找矿重点区域。