电子束光刻中邻近效应校正的几种方法

本文简要介绍了限制电子束光刻分辨率的主要因素之一-邻近效应的产生机制,列举了校正邻近效应的GHOST法、图形区密集度分布法和掩模图形形状改变法,介绍了每种方法的原理、步骤和效果,比较了它们各自的优缺点.     

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     

电子束曝光中的邻近效应修正技术

邻近效应是指电子在抗蚀剂和基片中的散射引起图形的改变，它严重地影响了图形的分辨率。有多种方法对邻近效应进行修正和剂量调整、图形调整等。我们以ＪＢＸ－５０００ＬＳ为手段，用三种方法：１．图形尺寸修正，１２大小图分类和剂量分配，３图形分层和大小电流混合曝光，对邻近效应进行了修正，均取得较好效果。     

三维结构的邻近效应校正

针对三维曝光图形的结构特点,结合重复增量扫描方式,分别从水平和深度两个方向进行邻近效应校正。水平方向通过预先建立校正过程中需要的各种规则表,使所需参数可以通过查表获得,快速、准确地实现了邻近效应校正,深度方向的校正则是从吸收能量密度与曝光剂量的关系上考虑。利用SDS-3电子束曝光机完成了校正实验。AFM图显示,邻近效应已大大降低,可满足三维加工精度的要求。所提出的扫描方式和校正方法为电子束曝光的三维加工和邻近效应校正提供了一种新方法。     

掩模制作中的邻近效应

计算模拟了激光束和电子束直写加工的掩模畸变,并分别用理想掩模和有畸变的掩模进行投影光学光刻过程的模拟和比较,讨论了光学邻近效应校正掩模在加工过程中所产生的畸变对传递到最终基片上的图形的影响。模拟分析指出,掩模加工中的邻近畸变应在设计光学邻近校正掩模时予以注意,即在掩模设计时,应把掩模加工中的邻近效应和光刻图形传递过程的邻近效应进行总体考虑,以便设计出最优化的掩模,获得最好的邻近效应校正效果。     

光学邻近校正改善亚微米光刻图形质量

论述了近年来光学邻近校正技术的进展,讨论了各种行之有效的改善光刻图形质量的校正方法,并分析了邻近效应校正是未来光刻技术中的地位和作用。     

低能电子束散射模拟在邻近效应修正中的应用

文章运用Monte Carlo方法模拟具有高斯分布特征的低能入射电子束斑在PMMA-村底中的复杂散射过程，分别得到了电子束在抗蚀剂中的穿透深度和能量沉积分布圈，并利用模拟结果进行邻近效应的修正．得到修正后的剂量数据文件。结果表明：采用修正后的剂量曝光，光刺胶中的能量沉积比较均匀．曝光分辨率有较大幅度的提高。该研究将对低能电子束曝光技术的定量研究和邻近效应修正技术的探索具有较高的理论指导意义。     

电子束光刻中的内部邻近效应校正技术研究

研究了基于图形几何尺寸修正的电子束光刻的内部邻近效应校正技术,利用累积分布函数预先进行内部最大矩形和顶点矩形的快速计算,并把它们存储在矩阵中。在校正过程中,根据初始矩形的尺寸,通过访问矩阵实现内部最大矩形和顶点矩形的快速替换。矩阵的预先建立,最大限度地减小了校正过程中的计算强度。模拟结果表明,通过内部最大矩形和顶点矩形的替换,能够快速地实现内部邻近效应校正,校正时间与被校正图形数目成线性关系增加。在与同类软件精度相同的情况下,提高了运算速度。     

亮暗衬线法校正邻近效应及其实验研究

光学光刻中的邻近效应校正是实现亚微米光刻的必要手段。作者基于波前加工的思想,提出亚分辨亮暗衬线结合辅助线条实现邻近效应校正的方法,分析了其校正机理,采用这种新方法,在可加工0.7μm光刻图形的I线投影曝光装置上加工出了0.5μm的光刻图形,取得了较好的实验结果,并与其它邻近效应的校正方法进行了比较。     

电子束光刻中邻近效应的Monte Carlo模拟

电子束光刻不受衍射效应的限制，具有高分辨率和能产生特征尺寸在100nm以下图形的优点。目前，国际上正在将角度限制散射的投影电子束光刻技术作为21世纪100纳米以下器件大规模生产的主流光刻技术进行重点开发。     

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...     

Implementation of electron beam grey scale lithography and proximity effect correction for silicon nanowire device fabrication

An electron beam lithography exposure strategy combining efficient proximity effect correction (PEC) with multi-pass grey scale is compared with a more conventional strategy based on a single-pass exposure without PEC. Exposure results for different types of nanowire structures are presented. Line edge and line width roughness (LER and LWR) values for both approaches are determined. The novel exposure strategy presented in this work reduced LER by ∼25% and LWR by ∼40%.     

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate,such as high density biochips, flexible electronics and liquid crystal display screens.     

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.     

角度限制散射投影电子束光刻

角度限制散射投影电子束光刻（SCALPEL）采用并行投影技术,具有分辨率高、曝光范围大的特点,可望获得远比电子束直写光刻高的产量。本文介绍了SCALPEL的原理、特点及该技术的研究进展情况。     

接近式光刻的计算机模拟研究

分析了菲涅耳近似模型在接近式光刻模拟中的应用和误差起源 ,并根据光的标量衍射理论 ,对菲涅耳近似模型进行了修正 ,得到了更加准确的类菲涅耳近似模型 ;并对这两种模型的模拟结果进行了比较     

Proximity-effect correction for VLSI patterns in electron-beam lithography

A proximity-effect correction method for VLSI patterns has been developed. In this method, a dose ratio has been introduced as a control parameter for the negative- resist thickness after development, in addition to the proximity parameters.A new technique has been used to obtain the proximity parameters. By using the dose ratio and the proximity parameters, both the exposure dose and the size of the irradiated shape are easily determined.A pattern accuracy of ±0.1 μm and a uniform resist of the desired thickness were obtained. The computation time is proportional to 1.2 power of pattern density, and is 100 seconds on a 1.5-MIPS computer when correcting for 10⁴ shapes in a pattern whose pattern density is 10⁴.     

化学放大胶在电子束光刻技术中的应用

化学放大胶(ChemicallyAmplifiedResists,简称CARs)是下一代光刻技术中极具发展潜力的一种光学记录介质。介绍了化学放大胶在电子束光刻技术中图形制作工艺的关键步骤以及目前常用的几种化学放大胶,分析了将化学放大胶用于电子束曝光工艺应注意的问题和它将来的发展趋势。