振幅分割无掩模激光干涉光刻的实现方法

无掩模激光干涉光刻中的分束方法一般有波前分割和振幅分割。研究和比较了振幅分割无 掩模激光干涉光刻方法和系统,包括振幅分割双光束干涉系统、三光束干涉系统、液浸式深紫外干涉系统及全自动干涉光刻系统。建立了双光束双曝光干涉光刻实验系统。模拟和实验结果表明,对点阵或孔阵图形,在同样的图形尺度下,无掩模干涉光刻比传统光刻简单得多。     

用多光束干涉实现纳米级阵列图形的长焦深光刻

用多束相干光适当组合干涉曝光,得到的图形与基片在干涉场内的纵向位置z无关,与x、y位置呈周期关系,光的相干长度对应传统光学光刻的焦深。该方法适合大尺寸基片上纳米级孔、锥阵列图形的制作。模拟了双光束双曝光、三光束单曝光和四光束单曝光的干涉场光强分布,用波长为441.6nm的激光曝光得到尺寸为200nm的孔阵和点阵的图形。     

用于大面积周期性图形制造的激光干涉光刻

用两束或多束相干激光束以不同的组合形式对光致抗蚀剂曝光,可在大面积范围内产生精细的二维周期性图形,这个方法特别适合于产生光电子器件和生电子器件的周期性结构。介绍激光干涉光刻的基本原理,对几种光束组合干涉方法给出了理论推导结果,并进行了计算机模拟。初步的实验结果表明,用激光干扰光刻技术产生大面积的亚微米级周期性孔、柱、锥图形是可行的。该方法不需要掩模、昂贵的光刻成像透镜、新的短波长光源和新型的抗蚀剂,提供了得到高分辨、无限焦深、大面积光刻的可能性。     

双光束双曝光与四光束单曝光干涉光刻方法的比较

双光束双曝光和四光束单曝光是无掩模激光干涉光刻的两种典型方法,都容易利用现有光刻工艺,在不需掩模和高精度光刻物镜的情况下,用简单廉价光学系统在大视场和深曝光场内形成孔阵、点阵或锥阵等周期性图形。双光束双曝光法得到的阵列图形周期极限为λ/2;四光束单曝光的周期略大,为前者的2倍。模拟和实验结果表明,通过控制曝光和显影工艺,双光束双曝光较四光束单曝光能更灵活地得到孔阵或点阵,而四光束单曝光得到的图形孔与孔之间没有鞍点,较双光束双曝光形成的孔侧壁更陡。这两种方法在需要在大面积范围内形成孔或点这类周期阵列图形的微电子和光电子器件的制造领域有很好的应用前景。     

成像干涉光刻技术及其频域分析

传统光学光刻技术(OL)由于其固有的限制,虽然可对任意图形成像,但分辨力较低。无掩模激光干涉光刻技术(IL)的分辨力可达l /4,却局限于周期图形。成像干涉光刻技术(IIL)结合了二者的优点,用同一个系统分次传递物体不同的空间频率,能更有效地传递物体的信息,以高分辨力对任意图形成像。初步模拟研究表明,在同样的曝光波长和数值孔径下,对同样特征尺寸的掩模图形,IIL得到的结果好于OL。在CD=150nm时,IIL相对于OL把分辨力提高了1.5倍多。     

用于KrF准分子激光光刻的三相移掩模

讨论了相移掩模提高光刻分辨力的基本原理,提出了一种抗蚀剂相移器制作衰减相移掩模的新方法,利用自行设计、建立的ＫｒＦ准分子激光投影光刻实验曝光系统进行了实验研究,给出了实验结果,并与传统光刻方法作了比较。     

制作光纤光栅的相移掩模-双光束干涉曝光方法

介绍将无铬相移掩模技术和双光束干涉曝光技术用于制作纳米级图形光纤光栅的基本原 理和实验系统设计。提出一种用可移动反射镜使写入光束扫描固定在一起的相移掩模和光纤组合体制作光纤光栅的方法,既便于系统调整,增强曝光能量,又可方便制作高分辨力、长尺寸光纤光栅,无论是周期光栅,还是非周期光栅。     

用于KrF准分子激光光刻的衰减相移掩模

讨论了相移掩模提高光刻分辨力的基本原理,提出了一种抗蚀剂相移器制作衰减相移掩模的新方法,利用自行设计、建立的KrF准分子激光投影光刻实验曝光系统进行了实验研究,给出了实验结果,并与传统光刻方法作了比较.     

采用双向偏置曝光的成像干涉光刻技术

成像干涉光刻技术(IIL)具有干涉光刻技术(IL)的高分辨力和光学光刻技术(OL)产生任意形状集成电路特征图形的能力。在IIL中,按掩模图形的不同空间频率成份分区曝光,并使其在抗蚀剂基片上非相干叠加,得到高分辨抗蚀剂图形。本文在研究一般三次曝光IIL原理基础上,提出采用沿X轴正、负方向以及沿Y轴正、负方向偏置的双向偏置照明,分别曝光 X方向、-X方向、 Y方向、-Y方向的高空间频率分量并与垂直于掩模方向的低空间频率分量曝光相结合的五次曝光IIL。理论和计算模拟表明,该方法可以提高图形对比度和分辨力,并减小因调焦误差引起的图形横向位移误差,有利于改善抗蚀剂图形质量。     

同步辐射光刻光束线的真空系统

第一条同步辐射光刻光束线已在合肥国家同步辐射实验室建成，并刻出了线宽0．2μm的图形。真空系统是光束线的重要组成部分。该真空系统要使镜箱内的压力分别小于6．7×10-8Pa（镜箱内有SR）和2．6×10-7（镜箱内无SR），以免暴露于SR的光学镜面遭受碳污染。一个装有可移动样品架的曝光室坐落在超净室中。曝光室内的压力约为10-4Pa。一个多级差分抽气系统实现了镜箱到曝光室的真空过渡。具有较大截面的差分管必须是良好的光通路。给出了差分抽气系统的计算公式和实验结果。描述了真空联锁系统的组成部分和功能。该光束线的功能还需扩展和提高，真空系统也有值得探讨和改进的问题。     

光学邻近效应与掩模特征尺寸的关系

依据物的空间频谱分布，部分相干成象理论及空间滤波概念，分析了投影光刻中的掩模特征尺寸与光学邻近效应的关系，并通过成象系统的数值孔长对ＯＰＥ的影响的模拟验证了分析结果。     

Simple and cost-effective fabrication of size-tunable zinc oxide architectures by multiple size reduction technique

Abstract

We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO) architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol–gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL). The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm^?2 and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL.     

Large-Area Reflective Infrared Filters for Millimeter/Sub-mm Telescopes

Ground-based millimeter and sub-millimeter telescopes are attempting to image the sky with ever-larger cryogenically-cooled bolometer arrays, but face challenges in mitigating the infrared loading accompanying large apertures. Absorptive infrared filters supported by mechanical coolers scale insufficiently with aperture size. Reflective metal-mesh filters placed behind the telescope window provide a scalable solution in principle, but have been limited by photolithography constraints to diameters under 300 mm. We present laser etching as an alternate technique to photolithography for fabrication of large-area reflective filters, and show results from lab tests of 500-mm-diameter filters. Filters with up to 700-mm diameter can be fabricated using laser etching with existing capability.     

Dove prism with increased throughput for implementation in a rotational-shearing interferometer

An analytical expression is derived for the tilt introduced into a wave front by a Dove prism with manufacturing errors in the prism's base angles and pyramidal angle. We found that the tilt decreases when the base angles are increased above the values of traditional design. The increase in the length-aperture ratio of a prism is detrimental to the prism's performance. However, a Dove prism with a widened aperture increases throughput and maintains a manageable prism weight for implementation in a rotational shearing interferometer. Thus we propose a Dove prism designed with a widened aperture to increase throughput in a rotational shearing interferometer and with larger base angles to minimize the wave-front tilt introduced by manufacturing errors. Experimental results implemented in a rotational shearing interferometer demonstrate the feasibility of this design.     

Lithographic patterning of superconducting YBCO films

Microbridges of YBa₂Cu₃O₇ thin films have been fabricated by conventional photolithography and wet chemical etching using EDTA, and by the lift-off lithography technique. The variation of etch rate with etch time, etchant temperature, and post-deposition sintering temperature has been studied. It has been shown that both techniques are useful for film patterning. However, an additional sintering step is necessary for the chemically etched sample to regain the original film properties. An order of increase in critical current density is observed for the patterned film.     

Rapid,Controllable Fabrication of Regular Complex Microarchitectures by Capillary Assembly of Micropillars and Their Application in Selectively Trapping/Releasing Microparticles

A simple strategy to realize new controllable 3D microstructures and a novel method to reversibly trapping and releasing microparticles are reported. This technique controls the height, shape, width, and arrangement of pillar arrays and realizes a series of special microstructures from 2‐pillar‐cell to 12 cell arrays, S‐shape, chain‐shape and triangle 3‐cell arrays by a combined top down/bottom up method: laser interference lithography and capillary force‐induced assembly. Due to the inherent features of this method, the whole time is less than 3 min and the fabricated area determined by the size of the laser beam can reach as much as 1 cm², which shows this method is very simple, rapid, and high‐throughput. It is further demonstrated that the ‘mechanical hand’‐like 4‐cell arrays could be used to selectively trap/release microparticles with different sizes, e.g., 1.5, 2, or 3.5 μm, which are controlled by the period of the microstructures from 2.5 to 4 μm, and 6 μm. Finally, the ‘mechanical hand’‐like 4‐cell arrays are integrated into 100 μm‐width microfluidic channels prepared by ultraviolet photolithography, which shows that this technique is compatible with conventional microfabrication methods for on‐chip applications.     

Modulation effect of the atmosphere in a pyramid wave-front sensor

The pyramid wave-front sensor in its original form works with a mechanical modulation that adapts the linear range of the sensor to seeing and sensing conditions. For adaptive optics systems working in an astronomical context, the way in which the aberrations produced by the atmospheric turbulence, which are not seen by the sensor owing to its limited temporal bandwidth, act as modulators is shown. These aberrations have the same effect of increasing the linear range and localizing the measurement as does mechanical modulation. The effect of residual wave-front aberrations is estimated for some example conditions of telescope diameter, system bandwidth, wind velocity, and Fried parameter.