Experimental analysis and optimization of a photo resist coating process for photolithography in wafer fabrication

This investigation is applied the Taguchi method and combination the analysis of variance (ANOVA) to the photo resist (PR) coating process for photolithography in wafer manufacturing. Plans of experiments via nine experimental runs are based on the orthogonal arrays. In this study, the thickness mean and the uniformity of thickness of the PR are adopted as the quality targets of the PR coating process. This partial factorial design of the Taguchi method provides an economical and systematic method for determining the applicable process parameters. Furthermore, the ANOVA prediction of the thickness mean and the uniformity of thickness for the PR has been applied in terms of the PR temperature, chamber humidity, spinning rate, and dispensation rate by means of the designs of experiments (DOE) method. The PR temperature and the chamber humidity are found to be the most significant factors in both the thickness mean and the uniformity of thickness for a PR coating process. Finally, the sensitivity study of optimum process parameters was also discussed.     

薄膜均匀性的有限元算法

应用有限元方法模拟计算了镀膜系统平行平面转盘在不同转速以及不同的镀膜时间下波分复用(DWDM)系统介质滤光片的成膜均匀性。结果表明,针对不同的膜料,合理选择转速和控制镀膜时间能够提高薄膜成膜的均匀性。     

Real-time predictive control of photoresist film thicknessuniformity

With the trends toward larger wafer size and the linewidth going below 100 nm, one of the challenges is to control the resist thickness and uniformity to a tight tolerance in order to minimize the thin-film interference effect on the critical dimension. In this paper, we propose a new approach to improve resist thickness control and uniformity through the softbake process. Using an array of thickness sensors, a multizone bakeplate, and advanced control strategy, the temperature distribution of the bakeplate is manipulated in real time to reduce resist thickness nonuniformity. The bake temperature is also constrained to prevent the decomposition of a photoactive compound in the resist. We have experimentally obtained a repeatable improvement in resist thickness uniformity from wafer-to-wafer and across individual wafers. Thickness nonuniformity of less than 10 Å has been obtained. On average, there is 10 × improvement in the thickness uniformity as compared to conventional softbake process     

锁相红外检测技术对耐候涂层厚度的评估

输变电设施的金属构件容易受温度、湿气等气候因素影响而发生侵蚀,因此通常需要在其表面喷涂耐候保护涂层.为了确保涂层厚度符合要求,需要对其进行检测.针对现有检测方法的不足,本文采用锁相红外无损检测技术对耐候涂层厚度进行检测与评估.首先采用制作的标准涂层试件对该方法测厚的原理与重复性进行验证,验证了该技术对涂层厚度的评估的可...     

脉冲激光沉积Al膜的沉积模式及沉积速率研究

为了给脉冲激光沉积(PLD)法沉积大面积均匀薄膜的应用提供相关的理论依据,以纯铝块作为靶材,采用PLD法在同轴和旁轴两种模式下对比研究了Al薄膜的厚度均匀性。同时,在旁轴的沉积模式下分别研究了基片温度、激光功率和重复频率对A l薄膜沉积速率的影响规律。实验结果表明,采用PLD方法在旁轴的沉积模式下获得的Al薄膜的厚度更加均匀。随着基片温度的增加,薄膜的沉积速率反而降低。升高激光功率,薄膜的沉积速率也随之提高。而在激光重复频率的变化过程中,Al薄膜的沉积速率有一最大值。     

一种用于检测薄膜均匀性的光谱方法

介绍了一种新的简单有效的薄膜均匀性信息获取方法,该方法基于我们先前提出的纳米薄膜厚度精确测量方法,它通过检测镀制在含有过渡层的衬底上不同位置的薄膜的光谱,并由其干涉峰间的差异获取薄膜的均匀性信息.与传统方法相比,该方法无需直接测量薄膜的厚度,减少了测量膜厚带来的误差和影响,因而可以快速得出薄膜均匀性结论.该方法操作方便...     

衍射光学元件制作中的基片涂胶方法

在基片上涂布一层厚度均匀的光刻胶层,是衍射光学元件制作中的一个重要步骤。介绍了目前用于衍射光学元件制作的两种主要涂胶方法———提拉法和旋转法,分析了这两种方法的特点和影响胶层厚度的主要因素,尤其是对其均匀性的影响,并提出了获得均匀胶厚的途径。对于提拉涂胶,选择粘度较高的光刻胶溶液与合适的提拉速度将有助于减小Marangoni流动和Van derWaals力对膜厚均匀性的影响;对于旋转涂胶,可以通过密封基片所在空间,或者通过气流控制器使基片上方空气流动处于层流状态来获得均匀一致的溶剂挥发速率,从而提高胶层的均匀性。     

Probe studies of plasma characteristics in the ICP reactor

The ICP plasma chemical reactor is studied by using the probe plasma diagnostic methods. The plasma density in the wafer region was evaluated at different parameters of the process. The automatic bias potential on the surface of glass wafers of different thickness and uniformity of the ion current density distribution over the plate diameter are measured. The deep silicon etching mode with a high uniformity over the whole plate is determined.     

利用ISSG退火改善隧穿氧化层的厚度均匀性

利用ISSG低压退火法来取代传统的氧气退火法,对沉积后的隧穿氧化薄膜进行退火处理.由于其独特的可控补偿氧化生长机制,最终在晶圆表面形成了厚度均匀的氧化层,薄膜质量也有了较大改善.这一结果为低压化学汽相沉积得到的隧穿氧化薄膜的平坦化提供了新思路.     

Four-dimensional dielectric property image obtained from electron spectroscopic imaging series

We have demonstrated a new quantitative method to characterize two-dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. In this study, Black Diamond/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced from two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.     

喷墨打印在液晶用彩色滤光片制造中的应用

彩色滤光片是液晶显示器件的重要组件,为了降低生产成本并提高显示性能,新型彩色滤光片制造技术的研发成为热点。喷墨打印具有快速、精准、材料利用率高等一系列优点,成为替代传统颜料分散法的新一代彩色滤光片制备技术。文章介绍了喷墨打印的基本原理,比较了喷墨打印成膜与传统涂布成膜的优缺点,分析了喷墨法制备彩色滤光片的技术关键,并根据目前的产业现状提出了努力方向。     

Spray-coating deposition techniques for polymeric semiconductor blends

We develop a universal method for spray-deposition of polymeric semiconductor blends, based on blends of polyfluorenes (F8TBT), polythiophenes (P3HT) and fullerenes (PCBM), as suitable for large areas. A multi-faceted characterisation approach, studying photoluminescence quenching, together with atomic force and optical microscopy, illustrates favourable results in terms of layer thickness, uniformity, and mesoscale morphology. With key engineering tolerances in mind, thermal (melt) and solvent-vapour annealing are investigated as post-processing methods, for improving the planarity of craterform layers and blend photophysical characteristics.     

利用分步试验设计表征/优化工艺空间均匀性

半导体制造工艺成品率对空间差异越来越敏感,需要表征与优化工艺空间均匀性.利用两步试验设计方法,针对六输入变量的热氧化工艺,仅需31次试验,便建立了表征工艺目标和空间均匀性响应曲面模型.利用该模型优化工艺,得到了满足其他工艺指标下工艺空间均匀性最优的工艺设置.片间非均匀性从1.44%减小到0.77%,片内非均匀性从0.2%减小到0.12%.     

Extrusion spin coating: an efficient and deterministic photoresist coating method in microlithography

Extrusion spin coating was developed to reduce photoresist waste and to improve coating uniformity in microlithography. This new method uses an efficient extrusion coating technique to apply a thin film of resist to a wafer prior to spinning. This initial layer of photoresist eliminates the spreading phase, the most inefficient step in conventional spin coating. The initial layer also provides existing spin coating models with preset initial conditions, allowing the prediction of coating thickness and uniformity a priori. This paper compares the experimental results with Emslie et al.'s predictive models of spin coating. A solvent concentration of 80% or higher in the coating chamber environment was found to be necessary to attain a predictable coating thickness with 5-/spl Aring/ uniformity. With optimized process variables, the mean coating thickness matched theoretical predictions within a variation of 0.01 /spl mu/m. Defect-free coating results were achieved with coating efficiencies as high as 40%.     

大面积头罩上类金刚石薄膜均匀性研究

根据军用光学仪器对红外窗口薄膜厚度均匀性的特殊要求,采用Femm42软件对射频等离子体化学气相沉积系统中真空室内的电场进行模拟分析,通过改变DOME的高度,并加入一金属圆环,解决了头罩边缘脱膜的问题。并利用田口实验方法指导实验,以减少实验次数,尽快找出影响薄膜性能的主次条件,同时可以分析各工艺参数对结果的影响趋势,最终确定最佳的工艺参数,在大面积头罩上成功镀制了厚度均匀性小于3%,且能承受恶劣环境测试的类金刚石薄膜。     

限流电阻层改善碳纳米管场发射显示器发光均匀度的研究

针对碳纳米管(CNT)场发射阴极薄膜中,CNT个体差异及其与衬底的不良接触对发光均匀性的影响,引入反馈限流电阻层以改善阴极薄膜的场发射发光均匀性.采用丝网印刷工艺在衬底上制备氧化锌作为电阻限流层,在其上制备CNT阴极薄膜.对CNT薄膜阴极的发射电流稳定性和均匀性进行了测试,给出了电阻限流层对场发射特性曲线的影响效果.SEM分析表明,氧化锌电阻层有利于消除CNT阴极的尖端屏蔽效应,并且使得CNT与衬底具有更加紧密的接触.场发射特性和场发射发光照片表明,虽然随着限流层厚度增加,阈值电压有所增加,发射电流有所减小,然而限流层的存在有效地改善了发射电流的稳定性,使得发射电流和场发射发光点分布更加均匀.     

New OMVPE reactor for large area uniform deposition of InP and related alloys

The deposition uniformity in a chimney reactor, with a sidearm to accommodate sus-ceptor rotation and mechanized substrate loading, has been characterized by mapping the thickness of InP deposited on 50-mm-diam. GaAs substrates. Susceptor rotation im-proves the thickness uniformity by approximately a factor of seven, with the thickness uniformity reproducibly held to less than 3% across 40 mm, under typical growth con-ditions. The deposition pattern is independent of rotation rate from 3 to 120 rpm, which corroborates the existence of a slow-rotation regime (observed in an earlier flow visu-alization study) where susceptor rotation does not disturb the gas flow. In agreement with that interpretation, the observed deposition pattern with susceptor rotation is about the same as that predicted from a circular average of the results without rotation. Also, some discussion is given of growth parameters which influence the surface morphology of heteroepitaxial InP on GaAs.     

反射式光纤传感器在涂层均匀度检测中的应用

文章用几何光学原理分析了反射光强与表面涂层厚度及均匀度的关系,提出一种用于检测物体表面涂层均匀度的方法.该传感器能针对物体表面涂层的随机性实现不同区域涂层均匀度的在线测试.在理论分析的基础上,构建了实验测试系统.数据表明,采用该传感器进行测试能反映表面涂层均匀度的变化,测试精度可达10μm,具有良好的应用前景.     

Evaluation and optimization of large area III-V epitaxial thickness uniformity using a Fabry-Perot microcavity test structure

We report a technique for simply and conveniently measuring epilayer thickness uniformity to 0.5% over an entire wafer. The technique requires epitaxial growth of a Fabry-Perot microcavity test structure. Mapping is performed by measuring the wavelength-dependent optical reflectivity at different points on the wafer and then fitting the reflectivity data to deduce the thickness uniformity. The mapping technique was used to determine the optimal growth conditions in a vertical rotating disk reactor that resulted in better than ±1% uniformity over a 2 inch wafer. The high precision of the optical reflectivity mapping technique can provide information not easily obtained with other techniques. For example, we show that the presence of wafer flat adversely affects the thickness uniformity.     

激光衍射技术在石墨卷材厚度自动测量中的应用

文中将激光衍射技术的测量推广到一个新的应用领域,即对宽度达1.5m的柔性石墨卷材进行测量.高质量的宽幅石墨卷材应用前景很广,但其生产过程要求必须有配套的实时、无损伤的测量监测系统.文中以小功率的激光器作为光源,提出了一套可以对其厚度和均匀性进行在线测量的方案--以相对比较测量法测厚度,以多点测量测均匀性.文中讨论了测量系统一些重要相关参数的选取;对测量装置给出了一些从实践中总结的改良措施;还对衍射条纹的信号处理进行研究.