Quantitative evaluation of proximity effect in raster-scan exposure system for electron-beam lithography

The proximity effect in a raster-scan for electron-beam lithography system was evaluated by Monte Carlo calculation and verified by experiments. It was revealed that the reduction in the beam diameter below the scanning pitch, which links into the shortening of drawing time, is more effective in decreasing the proximity effect than the reduction in the resist thickness. From the calculated results, it was found that the error in linewidth definition due to the proximity effect was less than 10 percent at a linewidth of 1.5 µm with scanning pitch of 0.5 µm, beam diameter of 0.2 µm, and PMMA resist of 1.0-µm thickness.     

一种有效的邻近效应修正方法

本文介绍了在电子束光刻中修正邻近效应的一种有效的剂量补偿方法。在其它曝光参数一定的条件下（包括加速电压,抗蚀剂厚度,曝光步长大小及衬底材料等）图形尺寸由剂量大小决定。本方法基于两种合理的假设来确定补偿剂量因子。一是假设在特定实验范围内,剂量的大小和圆直径的关系可以看作是线性的。二是假设补偿剂量因子仅受最近邻图形的影响。四层六角光子晶体作为本实验方法的测试图形。比较没有修正的结构,修正后的结构中孔大小的一致性得到了显著的提高     

An efficient dose-compensation method for proximity effect correction

A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography.The sizes of exposed patterns depend on dose factors while other exposure parameters(including accelerate voltage,resist thickness,exposing step size,substrate material,and so on) remain constant.This method is based on two reasonable assumptions in the evaluation of the compensated dose factor:one is that the relation between dose factors and circle-diameters is linear in the range under con...     

Investigation of photoresist-specific optical proximity effect

Optical proximity effects arising from individual resist characteristics are investigated. The parameters studied are those used in photoresist exposure and development simulation using the SOLID and Prolith/2 programs. The optical proximity effect is found to be independent of the exposure parameters but greatly affected by the development process and is shown to be a function of the Mack parameter, n, which is related to the resist contrast, γ. Finally, in order to put this effect into perspective with other resist selection criteria, the development parameter, n, is also shown to be related to wall angle and depth-of-focus (DOF).

The results of this investigation will therefore enable the user to select the most appropriate photoresist for a specific application.     

Analytical models for the series resistance of selective emitters in silicon solar cells including the effect of busbars

A theoretical analysis of the power loss and series resistance of the front side emitter in silicon solar cells is presented. Existing 1D models (infinitely long finger) and 2D models (including the effect of busbars) of emitter series resistance contribution are extended to the case of selective emitters. The general case of different current densities for both emitters in the selective emitter scheme is considered in these extensions. The resulting models depend on the individual sheet resistances and current densities in both emitters and the device's overall grid geometry. The models are corroborated by finite element simulation of the potential in the emitter. An excellent agreement is found between the analytical models, and the simulations for a wide range of sheet resistances typically encountered in silicon solar cells. Grid simulations using the 2D model are applied to solar cells with selective emitters, where the width of the low‐resistive emitter was varied. The simulations demonstrate that the 2D model can explain the absolute change in fill factor observed in these cells. Copyright © 2013 John Wiley & Sons, Ltd.     

A reliability model of a system with dependent components

A model of a multi-component system with dependent components in the time stationary case is presented. A procedure fits the parameters of the model with respect to given data such as the correlation coefficients. The system reliability of the fitted model is evaluated     

Minimal-cost system reliability with discrete-choice sets for components

We focus on systems whose components come from discrete choice sets. In a choice set, the alternatives have increasing cost with increasing reliability. The objective is to ensure minimal cost for achieving a specified reliability for the systems under consideration. Earlier work restricted itself to series-parallel/parallel-series (S/P) systems and provided formulations and algorithms. However, these are not amenable for dealing with more general systems. In this paper, we develop alternative formulations and algorithms based on a dynamic programming approach, and these are generalized for S/P-reducible systems. The algorithms we obtain are pseudo-polynomial and possess fully polynomial approximation schemes. Moreover, the formulations & algorithms are amenable for further generalizations to k-out-of-n : G and k-out-of-n : G-reducible systems, though we cannot claim pseudo-polynomiality in these cases. The results of this paper are useful for developing reliable systems at minimum cost. As such, the formulation & algorithms are of vital interest for systems & reliability professionals & researchers.     

Replacement vs. repair of failed components for a system with arandom lifetime

The computation of a variety of reliability measures for a system that is observed over a random time horizon is examined. This time interval, which can correspond to the system mission, the system lifetime, etc., is assumed to be distributed as a random variable of phase type. Models are developed that aid a decision-maker to choose among the actions of replace, repair, or do nothing, whenever a system component fails, under several assumptions concerning the amount of information available to the decision-maker. In addition, a policy of replacement after a fixed number of repairs is examined. An example computation of several reliability measures and the application of a cost model are included to illustrate the tractability of the results and their usefulness in design decisions     

图形改正方法在邻近效应修正中的应用

本文利用双高斯形式的邻近函数来表达电子束在抗蚀剂中能量的分布,并以邻近函数为基础计算一些简单图形在曝光时所需的尺寸改变量.通过与实验的比较来说明该方法的可靠性,并对所得结果进行讨论和分析.     

激光近炸引信半实物仿真与性能验证系统

研制该系统是为进一步完善激光引信的试验评测体系,为激光引信的性能测试及设计改进提供可重复进行的、量化的标准方法和全面的作战环境模拟.介绍了激光近炸引信半实物仿真及性能验证平台的系统组成、工作原理和关键技术.采用高速滑轨及姿态控制装置模拟弹目交会过程,目标及背景模拟装置模拟激光引信作战环境,通过采集、分析激光引信实物样机的回波、状态信息验证引信性能,采用FPGA开发平台对激光引信信息处理算法进行仿真验证,数字仿真平台开展激光引信虚拟设计验证.研制激光回波高速采集存储设备、模拟设备,建立激光引信数字仿真关键模型,解决了激光引信半实物仿真研究中的关键问题.该系统的建立可以克服外场试验人力物力耗费大、重复性差等弊端,缩短研制周期,降低研制成本拟合的方法.     

Integration of interdigital-gated plasma wave device for proximity communication system application

Interdigital-gated AlGaAs/GaAs high-electron-mobility transistor (HEMT) structure was used to investigate the interaction between the drifting carrier plasma waves and electromagnetic (EM) waves. It was shown theoretically that the interaction in the range from microwave to terahertz (THz) at room temperature should produce negative conductance characteristics when the carrier drift velocity slightly exceeds the phase velocity of EM waves. S-parameter reflection measurements were carried out at room temperature for a frequency range from 1 to 20 GHz and a drastic change in conductance was observed at 5 and 10 GHz with the increase of drain–source voltage. Large conductance change over 1000 mS/mm was obtained and it showed a peak at a certain frequency. The peak position could be controlled by changing the pitch size of the interdigital gates. These characteristics can be used for high-frequency applications such as high-speed switching devices although a feature size of our interdigital-gated HEMT device is much larger than conventional HEMT device.     

民机增强型近地告警仿真系统设计

增强型近地告警系统(EGPWS)是民航飞机上必需的航空电子设备,对保障飞行安全有重要的意义。增强型近地告警的仿真系统是研究增强型近地告警的一个有效手段,在VC 6.0平台下建立飞机的六自由度模型,人机交互界面和告警模块;利用Tilcon软件设计虚拟仪表并研究前视地形的显示方法;同时借助Flight Gear飞行模拟器实现飞行仿真的三维可视化显示,通过UDP通信将各个模块连接成一个完整的可视化仿真系统,实现对近地告警和飞行状态直观形象的显示。实验结果表明设计的系统能够对告警模式进行准确有效的报警,并具有可扩展性强、易操作的优点。     

LD redundancy system using polarization components for a submarine optical transmission system

An LD redundancy system having one cold standby laser diode is proposed to improve reliability in submarine optical transmission systems. This system makes use of the intrinsic laser polarization and consists of two LD modules and a polarization coupler connected by polarization maintaining (PANDA) fibers. The optical power insertion loss of this LD redundant system is 5.5 dB, including coupling loss between the laser diode and PANDA fiber. This LD redundant system will be applied in submarine optical repeaters.     

Wavelet-based time-domain solution of multiconductor transmission lines with skin and proximity effect

A time-domain wavelet-based method for the analysis of transmission lines (TLs) characterized by the presence of skin and proximity effects is presented. The method is based on the time domain TL equations, expressed in terms of transient resistance and convolution operator. A formulation of the convolution in the wavelet domain is presented here, and is used to expand the TL equations in the wavelet domain. In this way, the TL equations, properly discretized in the space variable, are reduced to an algebraic system characterized by a sparse block matrix whose blocks are easily calculated. The solution of the system is conveniently performed using standard techniques, avoiding step by step procedures. The method can be applied to linear and nonlinear problems, characterized by conductors of different shapes. The results obtained are compared with standard techniques, showing both accuracy and CPU time reduction.     

Analysis of three-dimensional proximity effect in electron-beam lithography

In most of the proximity effect correction schemes, a two-dimensional model of proximity effect is employed by ignoring or averaging the variation of exposure along the depth dimension in the resist. However, as the feature size continues to decrease, the relative variation becomes significant so that it may need to be taken into account in proximity effect correction. In this study, the three-dimensional (3-D) proximity effect is analyzed in detail through computer simulation as a first step toward developing a 3-D proximity effect correction scheme. Effects of the parameters such as beam energy, resist thickness, feature size, developing threshold, etc., on the 3-D spatial distribution of exposure in the resist, in particular, depth-dependent proximity effect, are considered in the analysis. Results from the extensive simulation are presented in this paper.     

光学邻近效应的产生机理分析

基于部分相干成像理论,考虑了投影曝光系统成像的非线性滤波特点,分析了投影光刻中的光学邻近效应（ＯＰＥ）产生的机理,模拟了掩模上线条的线宽,线间距的变化对光刻成像质量的影响。     

Reliability of a two-way circular consecutively connected system with multistate components

A two-way circular consecutively connected system with multistate components (two-way circular CCSMC) consists of n cyclically ordered components e₁,…,e_n, i.e. e_i+1, succeeds e₁, iε«ng l, …, n − 1ång;, e, succeeds e_n- Each component is capable of sending a signal in left-hand and right-hand directions. All components operate independently. The whole system is functioning if both left-hand and right-hand signals are received by each component. A recursive procedure evaluating the reliability of a two-way circular CCSMC is presented.     

Low-cost, redundant proximity sensor system for spatial sensing andcolour perception

The authors describe their approach to the design of redundant proximity sensor systems that are capable of extracting geometrical information about the surrounding environment and perceiving other relevant features of the reflecting objects, e.g. colour. Potential applications of the proposed sensorial systems are in the field of robotics and autonomous mobility     

A new type of high-efficiency bifacial silicon solar cell with external busbars and a current-collecting wire grid

Results regarding bifacial silicon solar cells with external busbars are presented. The cells consist of [n⁺p(n)p⁺] Cz-Si structures with a current-collecting system of new design: a laminated grid of wire external busbars (LGWEB). A LGWEB consists of a transparent conducting oxide film deposited onto a Si structure, busbars adjacent to the Si structure, and a contact wire grid attached simultaneously to the oxide and busbars using the low-temperature lamination method. Bifacial LGWEB solar cells demonstrate record high efficiency for similar devices: 17.7%(n-Si)/17.3%(p-Si) with 74–82% bifaciality for the smooth back surface and 16.3%(n-Si)/16.4%(p-Si) with 89% bifaciality for the textured back surface. It is shown that the LGWEB technology can provide an efficiency exceeding 21%.     

Coupling model and impedance calculation of the steel ground loops with proximity effect

This paper focuses on the coupling model and the coupling impedances between two circuits with a common ground of a steel plane. By adopting a two-dimensional (2-D) electromagnetic model, the influence of the skin and the proximity effects are considered. In the case of a strong proximity effect due to the exterior wires, the distribution of the electromagnetic field inside and outside a steel plane is analyzed, and an equivalent coupling circuit model of two circuits with a common steel plane is built. The analytical solution of the coupling impedances and its frequency characteristics are calculated based on the proposed model. The solution is validated by the numerical solutions and the measurement results in the frequency range of 40 Hz-15 M Hz. The influence of the proximity due to nearby wires is severe in high-frequency situations, and the internal impedance of the steel plane changes up to 100 times compared to that of the isolated steel plane.