光刻中驻波效应的影响分析

驻波效应是抗蚀剂在曝光过程中的寄生现象。一般认为,驻波效应对薄胶的光刻图形有较大的影响,而对厚胶的光刻图形影响不大。根据DILL曝光模型进行了模拟计算,分析了在曝光过程中抗蚀剂折射率的改变对驻波强度和位置的影响以及驻波效应引起抗蚀剂曝光剂量分布的变化,并结合MACK显影模型分析了当抗蚀剂的厚度改变时,驻波效应对其显影轮廓的影响程度,计算分析得出了一个可以不采用后烘工序的抗蚀剂厚度值。     

电子束光刻三维仿真研究

本文利用Monte Carlo方法及优化的散射模型,对电子束光刻中电子在抗蚀剂中的散射过程进行了模拟,通过分层的方法,对厚层抗蚀剂不同深度处的能量沉积密度进行了计算,建立了电子束光刻厚层抗蚀剂的三维能量沉积模型。根据建立的三维能量沉积模型,采用重复增量扫描策略对正梯锥三维微结构进行了光刻仿真。理论分析和仿真结果表明,利用分层的三维能量沉积分布模型能更精确地实现电子束光刻的三维仿真。     

厚胶光刻中光敏化合物浓度空间分布研究

厚胶光刻过程是一个复杂的非线性过程，其光刻胶内光敏化合物(PAC)浓度空间分布是影响显影面形的主要因素。根据厚层胶光刻的特点，结合光化学反应机理，利用角谱理论，分析了在曝光过程中光刻胶内衍射光场和PAC浓度的空间分布随时间的动态变化，以及后烘(PEB)过程对PAC浓度空间分布的影响。该方法数值计算结果准确，且速度快。数值模拟表明，其内部衍射光场分布与PAC浓度分布是一个动态的、非线性的相互影响过程；后烘工艺可平滑PAC浓度空间分布；PAC浓度空间分布是影响浮雕面形边沿陡度的一个重要因素。     

Estimation of resist profile for line/space patterns using layer-based exposure modeling in electron-beam lithography

One of the essential tasks in the dose control for fabrication of 2-D and 3-D patterns using electron-beam lithography is estimation of remaining resist profiles after development. A conventional approach is to compute the exposure distribution for a target pattern through convolution with the point spread function (PSF) and then obtain the resist profile via simulation of the development process based on the exposure distribution. A new approach which does not require calculation of the exposure distribution and simulation of the resist development is proposed. It utilizes a set of experimental results on which estimation of the resist profile is based, and has a good potential to provide an alternative to the conventional approaches. In this paper, the proposed approach is described in detail along with the results obtained from an extensive simulation and also experiments.     

抗蚀剂AZ4562曝光参数的变化趋势分析

针对厚胶曝光参数随不同光刻胶厚度及工艺条件变化的特点,在原有Dill曝光模型基础上,建立了适合于描述厚胶曝光过程的增强Dill模型,并将统计分析的趋势面法引入到厚胶曝光参数变化规律的研究中,给出了厚胶AZ4562曝光参数随胶厚及工艺条件的变化趋势,为开展厚胶光刻实验研究和曝光过程模拟提供指导性依据。     

光刻技术的现状和发展

着生从涂胶、曝光（包括光源和曝光方式等）、光刻胶和深度光刻等方面介绍了光刻技术的现状和未来的发展趋势。     

一种适于快速OPC的精确光刻胶剖面仿真算法

光刻仿真工具是描述实际工艺的有效工具。利用光刻仿真工具，能够准确地描述由掩模制造工艺、光刻胶曝光、显影、蚀刻所引起的光学邻近效应和畸变所导致的关键尺寸的变化。利用了改进的空间图像仿真及可变光强阈值模型来获得准确的硅片图形。改进的空间图像的基本思想是，用空间图像与一个高斯滤波器进行卷积，从而使图像较原来变得模糊，以此来模拟光刻胶的实际扩散效应。描述了一种适用于快速光学邻近校正（OPC）的准确的光刻胶剖面仿真算法。     

烘焙工艺条件对厚胶光刻面形的影响

采用厚层正性光刻胶AZ P4620进行光刻实验,考察了在前烘和坚膜阶段不同的工艺参数条件下的光刻胶浮雕面形的变化.实验表明,完全显影后光刻胶的浮雕面形受前烘工艺参数的影响很小,但其显影速率有一定差别;当坚膜烘焙后,不同前烘条件下的浮雕面形差别较大;当前烘条件相同时,坚膜参数的变化对光刻胶的浮雕面形影响较大.由此得出,在前烘阶段应采取较高温度、较短时间的烘焙,而在坚膜阶段应采取较低温度、较长时间的烘焙,这样可提高厚胶光刻面形的质量.     

Ion-beam etched multi-level resist technique for electroplating of submicron gold absorber patterns

A structuring process is developed which enables the fabrication of gold patterns by electroplating with a minimum linewidth of ? 0.3 μm. These patterns are used as mask patterns for X-ray lithography. They can be up to 1.6 μm thick. For this purpose, a resist pattern, which is generated by an electron beam, is transmitted to a multi-layer system by reactive ion-beam etching. The multi-layer system consists of a 2 μm thick polyimide layer, a 70 nm thick aluminum intermediate layer and a 30 nm thick gold passivation layer.With this process, X-ray masks with a polyimide membrane were produced and utilized for exposure to synchrotron radiation.     

侧墙铬衰减型新结构移相掩模的应用

提出了一种全新的移相掩模--侧墙铬衰减型移相掩模（SCAPSM) ，相对于通常的衰减型移相掩模，其制造工艺仅多两步，却可以较大幅度提高光刻分辨率. 采用PROLITH光学光刻模拟软件，参考ArF步进扫描投影光刻机TWINSCAN XT:1400E的曝光参数，对侧墙铬衰减型移相掩模的工艺进行了研究，证明SCAPSM+离轴照明的方案可以将干式193nm光学光刻的分辨率提高到50nm.     

Double-layer resist films for submicrometer electron-beam lithography

This paper describes a double-layer resist-film technique for submicrometer electron-beam lithography. The results of computer simulation and lithography experiments carried out on PMMA/MPR (LO/HI) and MPR/PMMA (HI/LO) double-layer films are reported in full detail. It is shown that an undercut profile suitable for the lift-off processing can be reproducibly obtained by the use of the LO/HI structure over a wide range of electron-beam exposure dose, while the HI/LO structure is of great advantage in the fabrication of lift-off metal gates with a mushroom-like cross section.     

E-beam lithography of computer generated holograms using a fully vectorial 3D beam propagation method

A fully vectorial 3D beam propagation method (BPM) has been applied to obtain a required pattern of computer generated hologram (CGH) with a variable profile of four phase levels. The computer reconstruction of the CGH image having one and two focal spots was performed by application of the fully vectorial 3D BPM method. After transferring the CGH by EBL technique an adequate phase profile was obtained. Inter-level parameter method was developed to obtain the estimated an electron beam dose required for the even topographical patterning. Using this method, an EBL exposure dose determined to achieve the required relief amplitude of 1.29 μm was 43 μC/cm². The manufactured holograms showed that the overall proposed production process, from the 3D BPM computer simulation to e-beam lithography, can be used to obtain good quality product with reasonable time and computational resources.     

Double-Layer Resist Films for Submicrometer Electron-Beam Lithography

This paper describes a double-layer resist-film technique for submicrometer electron-beam lithography. The results of computer simulation and lithography experiments carried out on PMMA/MPR (LO/HI) and MPR/PMMA (HI/LO) double-layer films are reported in full detail. It is shown that an undercut profile suitable for the lift-off processing can be reproducibly obtained by the use of the LO/HI structure over a wide range of electron-beam exposure dose, while the HI/LO structure is of great advantage in the fabrication of lift-off metal gates with a mushroom-like cross section.     

减小光刻中驻波效应的新方法研究

光刻过程中，抗蚀剂内部光敏混合物（PAC）浓度受光场的影响呈驻波分布，导致抗蚀剂显影后的侧壁轮廓成锯齿状。分析了后烘（PEB）对PAC浓度分布的影响，模拟了不同后烘扩散长度下的抗蚀剂显影轮廓，从模拟结果可知利用后烘可明显减小驻波效应，得到平滑的抗蚀剂显影轮廓，提高光刻质量。     

厚层抗蚀剂曝光模型及其参数测量

针对厚层抗蚀剂曝光过程中存在诸非线性因素的影响，更新Dill曝光参数的定义，建立了适合描述厚层抗蚀剂曝光过程的增强Dill模型．光刻过程模拟的准确性与曝光参数的测量精度有很大关系，为此，建立了实时曝光监测实验装置，测量了不同工艺条件、不同厚度抗蚀剂的曝光透过率曲线，并演绎计算出曝光参数随抗蚀剂厚度和工艺条件的变化规律．最后给出了采用增强Dill模型进行曝光过程的模拟和实验结果的分析．     

缩小步进投影光刻机在碲镉汞红外探测器芯片工艺中的应用

光刻是制备碲镉汞红外探测器芯片过程中非常关键的工艺。目前绝大部分碲镉汞芯片制备都是使用接触式光刻技术,但是在曝光面型起伏较大的芯片时工艺均匀性较差,并且掩膜在与芯片接触时容易损伤芯片。针对接触式光刻的这些缺点,利用尼康公司生产的缩小步进投影光刻机开发了用于碲镉汞芯片的步进式投影曝光工艺。对设备的硬件和软件均进行了小幅修改和设置,使其适用于碲镉汞芯片。经过调试后,缩小步进投影光刻机在某些面型起伏较大的芯片上取得了更好的曝光效果,光刻图形的一致性得到了提升。实验结果表明,缩小步进投影光刻技术能够提高碲镉汞芯片的光刻质量,并在一定程度上改善了芯片制备工艺。     

蒙特卡罗模拟电子束光刻中30、50和100keV电子束入射在层结构样品中的能量耗散剖面

本文利用蒙特卡罗模拟给出了电子束光刻中 30、50、100 keV 电子束垂直入射到厚衬底硅上的薄膜(0.4m)电子抗蚀剂聚甲基丙烯酸甲酯聚合物(PMMA)中的能量耗散剖面,模拟了理想点源和高斯圆束点源电子束情况下的膜中的径向散射和能耗,包括来自衬底的背散射,计算的电子数为三万到五万个。     

Interferential lithography of 1D thin metallic sinusoidal gratings: Accurate control of the profile for azimuthal angular dependent plasmonic effects and applications

Nonlinear processes involved in the manufacture of nominally sinusoidal surface relief diffraction gratings generated by interference lithography can introduce distortions into the profile of these surfaces. Such distortions may dramatically affect both the specular reflectivity and diffracted efficiencies from such a surface [H. Raether, Phys. Thin Film 9 (1977) 145–261]. We shall consider in particular the case of metallic gratings used to investigate plasmonic effects that can be engineered for bio-sensing applications. To investigate these effects, interference lithography (IL) has been used for the generation of profile controlled sinusoidal plasmonic crystals. IL exposure contrast study has been performed to control the amplitude oscillation and the surface roughness quality. Bi-metallic layer of silver and gold have been systematically deposited with different film thicknesses. A comprehensive numerical model that studies the optical coupling to surface plasmon polaritons on Ag/Au gratings has been undertaken for the simulation of the reflectivity and azimuthal angle dependence [Z. Chen, I.R. Hooper, J.R. Sambles, J. Opt. A: Pure Appl. Opt. 10 (1) (2008) 015007]. This computation illustrates the sensitivity of individual features to specific harmonic components of the surface, for surface plasmon resonances recorded in both the zeroth and higher diffracted orders. The roughness surface control after development and after bi-metallic evaporation strongly contributes to tighten the width of the reflectivity peak. Optimization process has shown that for an Ag (37 nm) and Au (7 nm) metallic bilayer, a semi-amplitude of 20 nm provides the best reflectivity.     

Monte Carlo simulation of the energy dissipation profiles of 30, 50 and 100 keV incident beams in a layered structure in electron beam lithography

This paper presents a Monte Carlo simulation of the energy dissipation profiles of 30, 50 and 100 keV incident beams in thin film (0.4μm) of electron resist, polymethyl methacrylate (PMMA), on thick silicon substrate in electron beam lithography. The radial scattering and the energy loss of incident electrons (including backscattered electrons from the substrate) are simulated under the illumination of ideal point source and Gaussian round beam spot source, and the histories of 30000–50000 electrons are computed.