采用梯形棱镜波前分割的激光干涉光刻技术

光学光刻技术在微细加工和集成电路(IC)制造中一直是主流技术。随着IC集成度的提高,要求越来越高的光刻分辨力,但光学光刻的分辨极限受光刻物镜数值孔径(NA)和曝光波长(λ)的限制。激光干涉光刻技术具有高分辨、大视场、无畸变、长焦深等特点,其分辨极限为λ/4,在微细加工、大屏幕显示器、微电子和光电子器件、亚波长光栅、光子晶体和纳米图形制造等领域有广阔的应用前景。阐述了激光干涉光刻技术的基本原理。提出了一种采用梯形棱镜作为波前分割元件的激光干涉光刻方法。建立了相应的曝光系统,该系统可用于双光束、三光束、四光束和五光束等多光束和多曝光干涉光刻。给出了具有点尺寸约220nm的周期图形阵列的实验结果。     

激光全息法制备二维硅基图形衬底

理论上模拟了全息光刻法制备二维硅基图形阵列的光强分布和显影过程,通过改变激光波长及入射光与样品表面的夹角即可得到不同周期的二维图形.在此基础上,采用三束光一次曝光和湿法腐蚀图形转移技术,在n型(100)硅衬底上制备出了周期在亚微米量级的均匀二维图形阵列.该方法适合大面积硅基图形阵列的制作.     

激光全息法制备二维硅基图形衬底

理论上模拟了全息光刻法制备二维硅基图形阵列的光强分布和显影过程,通过改变激光波长及入射光与样品表面的夹角即可得到不同周期的二维图形.在此基础上,采用三束光一次曝光和湿法腐蚀图形转移技术,在n型(100)硅衬底上制备出了周期在亚微米量级的均匀二维图形阵列.该方法适合大面积硅基图形阵列的制作.     

用于PCB、HDI、IC载板的高精度多光束激光动态LDI技术

随着智能手机和掌上电脑等超薄、超精细电子产品的大量问世,并为用户广泛接受,其电子产品的小型化、高密度化已成为必然。这些新型电子产品的出现驱动了PCB、HDI和IC载板向更高精度方向发展。据Prismark预测到2014年其线宽L/S精度将会小于10μm/10μm。这使得传统的DMD直接成像式LDI设备将会面临着精度、速度等性能上难以满足高精度的实际需求。阐述了一种新型的用于线宽L/S小于10μm/10μm高精度、高速量产型多光束激光动态LDI技术。该技术是采用了像空间调制器DMD微反射镜阵列对激光束进行图形调制,在成像光系统中增加了与DMD反射镜阵列对应的微透镜阵列图形处理系统,在保证曝光面积不变的前提下缩小了曝光点。其曝光光斑可小于3μm以下。其微透镜阵列采用了多层结构,具有远心光路、空间滤波功能,使曝光焦深可达几百微米到几毫米,提高了设备的实用性和稳定性。采用DMD多光束倾斜扫描技术,实现了更加精细及高密度的曝光图形。采用了阵列式多光引擎同步曝光实现高精度量产型LDI设备。     

影干涉光刻技术

采用λ／２的光束复制出了更高分辨率极限的线间图形，它将电路图形的ＣＤ尺寸极限推进到λ／４，当采用１９３ｎｍ光源曝光时，ＣＤ尺寸为５０ｎｍ以下。干涉光刻技术（ＩＬ）探讨了这种周期性图形的最终极限。影像干涉光技术未来的发展，将使光学方法１００ｎｍ 下的电路图形成为可能。     

图像处理技术在透镜阵列孔板检测中的应用

透镜阵列广泛应用于光束波前测试中,对大尺寸光束的检测要求,产生了对波前进行全尺寸检测的大尺寸透镜阵列。为安装透镜阵列,其固定支架设计为多圆孔板,圆孔的位置将决定安装透镜的精度,需对其进行检测与评价。采用数字图像处理方法,通过对孔板图像的去噪、二值化、图形提取、中心定位等数字化处理,分析圆孔排布的精度,对透镜阵列的定标分析提供了依据。     

对胶体球光刻中单层胶体晶体曝光特性的研究

对胶体球光刻中单层胶体晶体(MCC)的曝光特性进行了研究。利用磁控溅射的方法在蓝宝石衬底上生长SiO2薄膜并旋涂光刻胶,通过固液界面自组装的方法在光刻胶上制备了单层胶体晶体。胶体球光刻利用单层胶体晶体作为微透镜阵列,通过紫外曝光的方法在光刻胶上制备微孔阵列。光刻胶上图形的周期性与胶体球的直径有关,并且大直径的胶体球的聚光性能要强于小直径胶体球,在曝光过程中随着曝光时间的增加,由于曝光量的增加以及光刻胶的漂白现象,光刻胶上微孔的尺寸也在增加。最后以曝光后的光刻胶为掩膜,将感应耦合等离子体刻蚀技术(ICP)以及湿法腐蚀相结合,制备出了图形化蓝宝石(PSS)衬底。     

大阵列CCD光刻图形拼接技术研究

针对大阵列CCD工艺制作过程中光刻大面积图形曝光的需求,提出了一种适用于光刻拼接的图形补偿方法.图形拼接处进行相反的补偿设计0.3 μm“凹陷”,曝光时拼接交叠0.3μm.光刻后,图形拼接处平滑、自然过渡,图形整体上拼接自然,较好地解决了光刻大面积图形曝光存在的固有图形缺陷问题,改善了光刻曝光图形的质量.     

一种基于空间光调制器的微透镜阵列制备技术

提出了一种基于空间光调制器的并行光刻制备微透镜阵列的技术。采用数字微反射镜器件输入光刻图形,结合热回流技术,制作任意结构和排布的微透镜阵列。无限远校正显微微缩光学系统的长焦深保证了深纹光刻的实现,热回流法提供了良好的表面光滑度。与传统逐层并行光刻和掩模曝光技术相比,提出的技术方案更加便捷灵活,特别适合制作特征尺寸在数微米至百微米的微透镜阵列器件。得到的微透镜阵列模版经过电铸转移为金属模具,利用紫外卷对卷纳米压印技术在柔性基底上制备微透镜阵列器件,在超薄液晶显示、有机发光二极管(OLED)照明等领域有广泛应用。     

一种提高无掩膜光刻机图形质量的方法

针对无掩膜光刻技术在进行大面积图形曝光时会出现曝光质量差,精度低,程序繁等问题,该文提出了一种改善无掩膜光刻机图形质量的方法。通过设置“L”型定位标记将图形尺寸进行精确定位,再通过单场图像格式重命名系统,解决大面积图形切割过程中的乱序问题,最后提出了一种寻找最佳曝光位置的方法,以提高单场图形的曝光质量。该文提出了一种减小大面积图形拼接误差的方法,以提高整体图形的拼接质量;同时还提出了一种二次光刻的对准方法及对准误差校正方法,该方法与已有的套刻方法有区别。通过实验进行验证和分析,结果表明,该方法能有效地提高大面积图形的曝光质量,x、y方向的拼接误差距离均缩小到1 μm内,对准误差精度达到±0.3 μm。该研究为后续的光刻工艺及湿法腐蚀工艺奠定了理论基础。     

SiO2 single layer for reduction of the standing wave effects in the interference lithography of deep photoresist structures on Si

We demonstrate that the use of a single SiO₂ film, with thickness corresponding to one standing wave (SW) period allows the recording of deep photoresist structures on silicon substrates by laser interference, without use of any additional antireflecting coating. This condition corresponds just to the opposite thickness (half SW period) previously proposed for using the SiO₂ films for phase-shifting the SW pattern. Theoretical and experimental results demonstrated that for the lithography of deep structures, the contrast of the SW pattern, the minimum light intensity of the SW pattern and the photoresist adhesion are the most important parameters of the process.     

High density self assembled nanoparticle film with temperature-controllable interparticle spacing for deep sub-wavelength nanolithography using localized surface plasmon modes on planar silver nanoparticle tunable grating

A novel photolithographic technique using a periodic hexagonal close packed silver nanoparticle 2D array photo mask has been demonstrated to transfer a nano-pattern into a photoresist using G-I line proximity photolithography. This method can be made to precisely control the spacing between nanoparticles by using temperature. The high-density nanoparticle thin film is accomplished by self assembly through the Langmuir-Schaefer (LS) technique on a water surface and then transferring the particle monolayer to a temperature sensitive polymer membrane. A 30 nm hexagonal close packed silver nanoparticle 2D array pattern with a 50 nm period has been successfully transferred into S1813 photoresist using I-line exposure wavelength. The resultant feature sizes were 34 nm with a period of 46 nm, due to the surface plasmon resonance where the S1813 photoresist feature is approximately 11 times smaller than I-line exposure wavelength.     

Constrained Order in Nanoporous Alumina with High Aspect Ratio: Smart Combination of Interference Lithography and Hard Anodization

With only two matched processing steps, the fabrication of thick nanoporous alumina membranes with mono‐oriented, perfect hexagonal packing of pores, and precise control of all structural parameters over large areas is demonstrated. The cylindrical pores are uniform in shape and widely tunable in their dimensions and spatial distribution, with aspect ratios as high as 500. In brief, electropolished aluminum is first patterned using three‐beam interference lithography in a single step and then anodized in a hard regime. The periodic concavities in the aluminum surface guide the pore nucleation, and the self‐ordering phenomenon guarantees the maintenance of the predefined arrangement throughout the entire layer. In contrast to other methods, the interpore distance can be easily adjusted, the porous layer is not limited in thickness, no prefabricated stamps are involved, and the periodic pattern can be easily reproduced without risk of degradation. The approach overcomes the time, cost, and scale limitations of other existing processes. These membranes are well‐suited for the templated fabrication of perfectly ordered arrays of highly uniform 1D nanostructures. Thus, the application fields of these functional membranes are diverse: magneto‐optical and opto‐electronic devices, photonic crystals, solar cells, fuel cells, and chemical and biochemical sensing systems, to name a few.     

Rational and Facile Construction of 3D Annular Nanostructures with Tunable Layers by Exploiting the Diffraction and Interference of Light

This paper reports a rational and facile approach to fabricating arrays of 3D annular nanostructures with tunable layers by utilizing the diffraction and interference of UV light. Based on discretized Fresnel bright spots and standing waves formed within a photoresist film, the structures with nanoscale features are realized using simple, conventional photolithography. The 3D annular nanostructures are produced in arrays of single‐, double‐, and triple‐layered ring structures with the height of single layer on a 100 nm scale. The structural formation process and features of the nanostructures are analyzed and explained through 3D modeling that integrates the effects of both UV exposure dose and chemical kinetics. The approach to generating 3D annular nanostructures with tunable layers and discrete heights can be adapted for various applications that require the 3D structures fabricated over a large area with high throughput.     

全息光刻和二次显影法制备柱形二维光子晶体

采用全息光刻和二次显影的方法制备了柱形二维光子晶体.在此过程中,二维点状的周期结构首先在正性光刻胶上直接形成,然后经由Si3N4硬掩模转移到衬底材料上.利用二次显影的方法,曝光强度最强和曝光强度中等区域的光刻胶能够被同时充分显影,而曝光强度最弱区域的光刻胶则可以完全被保留下来.通过调节入射角,可以方便地调节二维结构的周期.利用此方法,在相对较大的面积上制备了不同周期的二维结构,二维结构具有很好的均匀性和重复性.文章对有关的工艺参数进行了详细讨论.     

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。     

用相干刻蚀制作大面积的二维纳米阵列

采用多级激光扩束获得大面积的均匀光场分布，利用相干刻蚀(IL)技术，制作了大面积(3．23cm^2)的二维(2D)周期阵列结构，如光栅和栅格，并以此阵列制备出空间周期为300nm的金属Ag、Au和磁性材料Ni的点阵结构。     

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

This paper describes soft lithography methods that expand current fabrication capabilities by enabling high‐throughput patterning on nonplanar substrates. These techniques exploit optically dense elastomeric mask elements embedded in a transparent poly(dimethylsiloxane) (PDMS) matrix by vacuum‐assisted microfluidic patterning, UV–ozone‐mediated irreversible sealing, and chemical etching. These protocols provide highly flexible photomasks exhibiting either positive‐ or negative‐image contrasts, which serve as amplitude masks for large‐area photolithographic patterning on a variety of curved (and planar) surfaces. When patterning on cylindrical surfaces, the developed masks do not experience significant pattern distortions. For substrates with 3D curvatures/geometries, however, the PDMS mask must undergo relatively large strains in order to make conformal contact. The new methods described in this report provide planar masks that can be patterned to compliantly compensate for both the displacements and distortions of features that result from stretching the mask to span the 3D geometry. To demonstrate this, a distortion‐corrected grid pattern mask was fabricated and used in conjunction with a homemade inflation device to pattern an electrode mesh on a glass hemisphere with predictable registration and distortion compensation. The showcased mask fabrication processes are compatible with a broad range of substrates, illustrating the potential for development of complex lithographic patterns for a variety of applications in the realm of curved electronics (i.e., synthetic retinal implants and curved LED arrays) and wide field‐of‐view optics.     

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。