Characterization of a nano line width reference material based on metrological scanning electron microscope

The line width(often synonymously used for critical dimension,CD)is a crucial parameter in integrated circuits.To accurately control CD values in manufacturing,a reasonable CD reference material is required to calibrate the corresponding instruments.We develop a new reference material with nominal CDs of 160 nm,80 nm,and 40 nm.The line features are investigated based on the metrological scanning electron microscope which is developed by the National Institute of Metrology(NIM)in China.Also,we propose a new characterization method for the precise measurement of CD values.After filtering and leveling the intensity profiles,the line features are characterized by the combination model of the Gaussian and Lorentz functions.The left and right edges of CD are automatically extracted with the profile decomposition and k-means algorithm.Then the width of the two edges at the half intensity position is regarded as the standard CD value.Finally,the measurement results are evaluated in terms of the sample,instrument,algorithm,and repeatability.The experiments indicate efficiency of the proposed method which can be easily applied in practice to accurately characterize CDs.

Diffraction Line Width in Quasicrystals—Sharper than Crystals

A quasicrystal has a structure intermediate between crystals and compound glasses. The disorder in glass makes its diffraction diffuse, so it is surprising that quasicrystals diffract more sharply than crystals. The greater sharpness is computed to be due to the hierarchic structure with unit cell alignment in 3-dimensional space. Electron microscope phase contrast images map the comparatively heavy Mn atoms in icosahedral Al6Mn, where the transition metal locates the centers of unit cells inside clusters and superclusters. Because the solid is aperiodic, each diffracted beam is a product of multiple interplanar spacings combined, and this contrasts with the unique relationship between spacing and incident angle in Bragg diffraction from crystals. Simulated quasi-structure factors add the relative phase shifts that are in geometric series from cell to cluster to superclusters of increasing order. The scattering becomes coherent in best fit, angular configuration between the aperiodic solid and a longitudinally periodic X-ray or electron probe. The quasi-structure factors express angular divergence in each diffracted beam from its corresponding Bragg condition, and the divergence provides a special metric, essential for atomic measurement in the geometric solids. The fit is reinforced at all levels from the unit cell to cluster to high order superclusters. The optics operates under a new quasi-Bragg law in a new geometric space. In this paper, we proceed to examine the effect of specimen size on line resolution in diffraction, first analytically and secondly in simulation. The line resolution follows a power law on the supercluster order, matching its atomic population.

Precise measurement of the line width of the photoassociation spectra of ultracold molecules by using a frequency shifter

We propose a technique to precisely measure the line width of the photoassociation spectra of the excited cesium molecule by using a frequency shifter to generate two laser beams with a precise frequency difference. A series of photoassociation （PA） spectra are recorded with two laser beam induced molecular lines, whose peak separation serves as an accurate frequency ruler to measure the line width of the PA spectra. The full width half maximum line width was studied as a function of PA laser intensity. The extrapolated value at zero laser intensity is （34.8± 0.22） MHz. By analyzing other broadening mechanisms, a value of （32.02 ± 0.70） MHz was deduced. It is shown that this scheme is inexpensive, simple, robust, and is promising for applications in a variety of other atomic species.

On the Vickers Microhardness and Wide-Angle X-Ray Line Width for Characterization of the Oxidative Stability of Poly(ethylene-co-propylene) Pipes

The purpose of the current study is to evaluate the ageing of poly(ethylene-co-propylene) fittings produced by several manufacturers. The fittings were aged for varying times as follows: 0, 2, 13, 23, 45, 106, 225 and 391 days at 100°C. In a previous paper, the oxidation induction time (OItime) and oxidation induction temperature (OItemp) were evaluated with respect to every single step of the ageing process [1]. Here, the Vickers microhardness and wide-angle X-ray line width were used for characterization of the oxidative stability of poly(ethylene-co-propylene) pipes. Both the Vickers microhardness and wide-angle X-ray line width as evaluated from a certain reflex of the diffractogram generally increase with ageing for most samples. The higher microhardness is most likely related to higher fragility of the pipes. The increase of the X-ray line width with ageing indirectly proves that reducing the crystallite size as well as increase of the crystallite defectiveness take place.

Variation of the Observed Widths of La I Lines with the Energy of the Upper Excited Levels, Demonstrated on Previously Unknown Energy Levels

We performed systematic laser spectroscopic investigations of La I spectral lines, using optogalvanic detection. Sixteen previously unknown even parity levels, having energies between 40,300 and 44,300 cm-1, are reported. These levels classify altogether 67 lines, not listed in spectral tables. The new levels were found due to the observation of the depopulation of the lower levels of the excited transitions. We found a remarkable variation of the observed widths of single hyperfine structure components dependent on the energy of the upper excited levels. Some levels having energies higher than 43,000 cm-1 appear to have a very high ionization probability.

水工高压隧洞钢筋混凝土衬砌裂缝开度数值模拟方法研究

水工高压隧洞常以裂缝最大宽度作为钢筋混凝土衬砌设计的控制标准,但针对大洞径、高水头隧洞的裂缝最大宽度计算,公式法存在一些局限性。许多专家学者尝试将数值模拟方法应用至衬砌裂缝宽度计算当中,但难以统筹考虑钢筋混凝土粘结滑移、裂缝开裂后的应力重分布等多重因素的影响。基于此,提出一种通过损伤模型指导布设虚拟裂缝单元以反应裂缝特征的方法,即首先利用考虑粘结滑移的混凝土损伤模型模拟钢筋混凝土联合作用下衬砌混凝土损伤随着荷载施加发展的过程,进一步对损伤集中区域增设虚拟裂缝单元以计算裂缝开展过程。经对比,采用该方法计算得到的裂缝最大宽度、发展规律与分布情况与既有文献相似,且计算收敛性好,实现了通过有限元算法精确且高效地直接得到衬砌裂缝宽度,在设计与运行安全预测方面具有较大的应用价值。

Comparison experiments of neon and helium buffer gases cooling in trapped ^(199)Hg^+ ions linear trap

The influences of different buffer gas, neon and helium, on 199^Hg^＋ clock transition are compared in trapped 199^Hg^＋ linear trap. By the technique of time domain＇s Ramsey separated oscillatory fields, the buffer gas pressure frequency shifts of 199^Hg^＋ clock transition are measured to be （df/dPNe）（1/f） = 1.8 × 10^-8 Torr^-1 for neon and （df/dPHe） （1/f） = 9.1 × 10^-8 Torr^-1 for helium. Meanwhile, the line-width of 199^Hg^＋ clock transition spectrum with the buffer gas neon is narrower than that with helium at the same pressure. These experimental results show that neon is a more suitable buffer gas than helium in 199^Hg^＋ ions microwave frequency standards because of the 199^Hg^＋ clock transition is less sensitive to neon variations and the better cooling effect of neon. The optimum operating pressure for neon is found to be about 1.0 × 10^-5 Torr in our linear ion trap system.

可变焦液体柱面透镜的设计与制作

文章设计并制作了一种基于电磁驱动的可变焦液体柱面透镜,并对其性能进行了测试与分析。研究结果表明:当工作电流在0到1.5A范围内变化时,该柱面透镜焦距随工作电流增大而逐渐减小,焦距变化范围为(8.97mm,+∞),最大横向放大率β为1.6,系统通电响应时间约为20ms,断电衰减时间约为25ms。当工作电流为1.5A时,该透镜的焦距为8.97mm,相应的焦线长度为11mm,焦线宽度为1mm。文章提出的液体柱面透镜,在光束整形、设备扫描和2D/3D可切换显示等领域具有潜在的应用前景。

钢筋锈蚀作用下隧道衬砌结构力学性能劣化研究

考虑锈蚀引起的钢筋力学性能劣化、混凝土有效截面减少、两者黏结性能退化等因素,建立围岩压力作用下钢筋锈蚀隧道衬砌模型,对不同锈蚀率下衬砌结构变形、损伤、内力重分布和裂缝宽度变化进行分析。研究结果表明,锈蚀对衬砌结构各部位损伤严重程度表现为拱顶>拱肩>拱脚>拱腰>仰拱;锈蚀引起结构内力重分布,当锈蚀率由0%发展到20%时,衬砌结构临空侧受拉处弯矩逐渐减小,围岩侧受拉处的弯矩逐渐增大,衬砌轴力整体变化不大,最大变化量仅为7.53%;拱顶裂缝宽度发展最快,拱肩和拱脚次之,当锈蚀率发展到2.7%时,拱顶最大裂缝宽度已不满足耐久性要求;开裂区钢筋锈蚀对衬砌力学性能劣化起主导作用,仅开裂区钢筋发生锈蚀时,衬砌结构力学性能劣化规律与钢筋全长锈蚀情况类似,但锈蚀导致的内力变化幅度和裂缝宽度减小。

Research on Total Electric Field for DC Lines Converted from Double-Circuit AC Lines

With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes.

Si/SiO_(2)多层膜线宽关键参数精细化表征技术研究

线边缘粗糙度(LER)和线宽粗糙度(LWR)是衡量线宽标准样片质量的重要指标。文中基于自溯源光栅标准物质的自溯源、高精密尺寸结构特性,提出了一种直接溯源型精确校准SEM放大倍率的方法,以实现SEM对线宽标准样片关键参数的测量与表征。利用校准后的SEM,对利用Si/SiO_(2)多层膜沉积技术制备的线宽名义值为500、200、100 nm样片进行关键参数的测量,采用幅值量化参数的均方根粗糙度RMS描述线边缘粗糙度与线宽粗糙度,并通过图像处理技术确定线边缘位置,对线宽边缘特性进行了精确表征。实验结果表明,名义值为500、200、100 nm对的线宽样片,其实测值分别为459.5、191.0、99.5 nm,σLER分别为2.70、2.35、2.30 nm,σLWR分别为3.90、3.30、2.80 nm,说明了多层膜线宽标准样片线边缘较为平整、线宽变化小、具有良好的均匀性与一致性。基于自溯源标准物质校准SEM的方法缩短了溯源链,提高了SEM的测量精度,实现了线宽及其边缘特性的精确表征,为高精度纳米尺度测量和微电子制造领域提供了计量支持。

沿黑体辐射线类太阳光LED调光系统调配及优化

为了使发光二极管(LED)光源光谱在可见光波段更接近太阳光光谱,且相关色温实现沿黑体辐射线连续可调,选取不同峰值波长LED芯片及荧光粉,覆盖可见光波段;采用相应LED芯片激发相应荧光粉,获得多个调光光源并记录色点及相对光谱;根据光谱叠加性原理,混合光源色点位于调光光源在CIE 1931色坐标图中围成的区域内。对四色光源混合调光进行了系统的调配优化,基于脉宽调制(PWM)调光模式,使用LED驱动模块控制各调光LED的光通量,实现了光源沿黑体辐射线色温可连续调节。模拟与实测结果显示,在常用照明色温2700~6500 K时,LED光源的一般显色指数大于98,且各特殊显色指数均大于90。光谱特性与太阳光类似,填补了LED白光中青光波段的凹陷,去除了短波长蓝光危害。

聚焦离子束工艺参数对单像素线刻蚀的影响

单像素线刻蚀是制备微纳米器件中的基本单元及加工其他复杂结构的基础,对聚焦离子束(FIB)加工具有重要的意义。通过改变离子束流的大小、驻留时间、扫描步长百分比及离子剂量等参数,对硅表面进行单像素线刻蚀的研究。结果表明,在聚焦离子束加工中,离子剂量与刻蚀线条宽度和深度之间呈正相关,与宽深比之间呈负相关;离子束流大小的变化对刻蚀深度影响不明显,但刻蚀宽度和宽深比随离子束流的增大而增大。此外,随着离子束流驻留时间增加,刻蚀宽度增大而深度减小;随着扫描步长百分比的增大,刻蚀深度增大,刻蚀宽度减小,分析结果表明这些变化与加工过程中再沉积作用有关。本研究成果为后续复杂图形的精密加工提供了重要参考依据。

FDM多工艺参数对PLA制件尺寸误差的影响

为探索熔融沉积快速成型技术(FDM)的工艺参数对聚乳酸(PLA)制件成型尺寸误差的影响规律,通过逆向数据采集方法对制件的长度误差、宽度误差、厚度误差进行测量对比,在4个单一工艺参数(外墙打印速度、外墙线宽、打印温度、打印层高)变化对尺寸误差影响分析的基础上,采用响应面法对筛选出的3个主要因素进行交互实验与分析。结果表明,长度误差受工艺参数的影响最大,其次是厚度误差,工艺参数对长度误差、宽度误差以及厚度误差的影响程度的排序均为:打印层高>打印温度>外墙线宽。

水工隧洞组合衬砌结构开裂特性研究

为研究铺设排水板的水工隧洞组合衬砌结构开裂特性,从结构变形协调的角度推导了多层厚壁圆筒模型理论公式。以珠江三角洲水资源配置工程某水工隧洞为依托,对无排水板铺设方案和全排水板铺设方案下组合衬砌进行受力分析;基于有限元软件LUSAS建立数值计算模型,采用塑性损伤多裂缝混凝土本构模型,探究排水板局部铺设下组合衬砌钢管变形和应力演化特征以及自密实混凝土的开裂特性。结果表明:无排水板方案下钢管只承载较小比例的内水压,全排水板方案下钢管承载约1/3的内水压,此时自密实混凝土均已达到开裂水平;开裂非线性分析表明,在自密实混凝土损伤开裂后钢管位移最大值位于腰部下侧靠近排水板末端,排水板铺设区域钢管应力达到屈服强度的1/3,未充分发挥承载能力;自密实混凝土裂缝发育大致表现为弹性阶段、起裂阶段、拓展阶段、波动阶段等4个阶段,新的表面裂缝产生后会迅速贯穿、拓展,并造成周围相邻两条裂缝轻微闭合,贯穿裂缝主要位于排水板铺设区域。研究成果可为组合衬砌结构优化设计提供参考。

箱形截面混凝土梁有效宽度通用计算算法研究

研究目的:箱形截面由于形式多样,可选拐点数量众多,导致截面有效宽度的计算复杂,且难以形成通用的计算算法。针对常规求解算法只适用于特定形式截面、通用性不足的问题,提出适用于箱形截面的有效宽度通用计算算法。研究结论:(1)基于节线将截面离散化处理,以得到适用于不同有限元软件数据格式的截面有效宽度;(2)通过分区域将截面解耦,分别计算局部节线再合并形成全局节线的方法,有效降低了节线计算复杂度,实现了复杂的多拐点截面有效宽度计算;(3)各区域节线计算模块相互独立,有效增加了各计算模块的通用性,减小了算法的维护工作量;(4)在各区域节线计算模块中,提出按特定的分类顺序依次形成多级子分支,并逐级对子分支计算节线的方法,确保了复杂的多拐点截面局部节线计算结果的准确性和完整性;(5)在本文算法的框架下,通过扩展实现了任意箱室数量箱形截面的有效宽度计算;(6)本文所述算法通用性强、适用范围广,可以高效地应用于混凝土桥梁的有限元建模中。

曝光单元内线宽均匀度优化对产品工艺窗口的提升分析

阐述随着半导体工艺节点的发展,关键光刻层的最小线宽变得越来越小,由此导致图形边缘位置误差容许范围也越来越小。其中曝光单元内线宽均匀度提升受光罩制作、曝光行为等多方面影响很难控制,导致很多产品在良率验证时出现在Field固定位置发生失效的问题。为此,探讨在28nm HKC+工艺的产品上使用不同的补偿方式优化曝光单元内线宽均匀度,旨在寻找快速高效的补偿方式降低Intra-field CDU,提升图形工艺的工艺窗口。

自来水笔线迹宽度测试研究

回顾了自来水笔线迹宽度的标准及其测试方法的演变,对影响自来水笔线迹宽度的因素进行了探讨。从线迹宽度的测试方法出发,对影响线迹宽度测试的书写荷载、书写纸等因素进行了研究,并实际测试了线迹宽度,分析了不同测试条件下的测试结果。最后对新版标准的贯彻实施提出了展望,对标准的完善提出了建议。

Q355B热轧钢卷边直发纹缺陷原因与控制

针对Q355B热轧钢卷边部直态发纹缺陷取样分析,通过电镜微观检验,并结合现场工艺确定了该类直态发纹形成原因为铸坯角部在减宽轧制时翻至上表形成的折叠类缺陷,距离边部8~30 mm,深度80~300μm。针对缺陷原因制定对应控制措施,钢卷边部直态发纹得到较好控制。

基于不连续边界识别的辫状河储层夹层研究——以渤海海域P油田馆陶组为例

渤海海域P油田发育河道切叠频繁的辫状河储层,已钻井揭示其储层内夹层发育,导致钻后水淹状态和产能差异较大,夹层精细刻画和精确表征是剩余油挖潜的关键。分析了P油田夹层分布特征及成因,认为夹层分布与构型边界具有较好的相关性,因此提出了基于不连续边界识别的夹层刻画方法。通过两级不连续边界分析识别出边界河道、内部主河道和内部次河道,分别对应复合心滩边界河道充填、单心滩边界河道充填和串沟充填3种夹层类型,建立了各级河道的定量判别标准,确定了夹层厚度中心线;根据研究区300个井组侧钻井资料,分析确定了夹层的平均厚度和翼展宽度;利用分类插值和井点校正得到了夹层厚度分布图。结果表明,P油田馆陶组辫状河储层夹层多以宽翼条带状分布,3种夹层的平均厚度分别为3、2和1m,平均翼展宽度分别为100、50和25m。应用本方法对C10井区L50小层进行了精细研究,夹层刻画结果有效指导了剩余油的挖潜。