基于最小平均相关能量滤波器的畸变目标识别

通过对多种畸变目标识别算法的研究, 对用于匹配滤波器的最小平均相关能量(MACE)滤波器进行了改进。利用MACE滤波器算法的基本思想构造滤波器函数, 在合成参考图像前对训练图像进行边缘提取, 并对联合图像的功率谱进行了拉普拉斯锐化, 成功实现了在联合变换相关器中对旋转目标图像的探测和识别, 提高了畸变图像相关峰的亮度, 拓展了联合变换相关器的探测和识别的范围。作为实例, 对旋转战机目标图像进行了计算机模拟实验和光学实验, 验证了该算法的可行性。     

基于最小平均相关能量滤波器的畸变目标识别

通过对多种畸变目标识别算法的研究,对用于匹配滤波器的最小平均相关能量(MACE)滤波器进行了改进。利用MACE滤波器算法的基本思想构造滤波器函数,在合成参考图像前对训练图像进行边缘提取,并对联合图像的功率谱进行了拉普拉斯锐化,成功实现了在联合变换相关器中对旋转目标图像的探测和识别,提高了畸变图像相关峰的亮度,拓展了联合变换相关器的探测和识别的范围。作为实例,对旋转战机目标图像进行了计算机模拟实验和光学实验,验证了该算法的可行性。     

改良型MACH滤波器算法的形变目标识别

联合变换相关器可用于精确识别与定位目标,其瓶颈在于如何在复杂背景中识别形变目标,这也限制了目标模式识别技术的发展.为解决这一问题,提出了一种改良型的最大平均高度(MACH)滤波器算法.该算法对于旋转形变及尺寸形变目标均有很强的识别能力.根据大量的实验结果分析,对合成滤波器的控制参数进行了优化,使得该滤波器具有较高的形变识别容差,并能有效抑制复杂噪声.通过将频域中改良的MACH滤波器返回至空域,可获得含有目标多种不同状态的MACH参考模板.利用该模板,能有效增强相关峰亮度,扩大复杂背景中形变目标的识别范围.作为实例,对复杂背景中的战舰目标进行了计算机模拟实验与光学实验.实验结果证明了该算法的可行性和实用性.     

基于CORDIC算法的数字滤波器设计

FIR和IIR数字滤波器广泛应用于各种数字信号处理系统。从坐标旋转公式出发，阐述了CORDIC算法的原理．同时在FPGA上实现了该算法的设计，并且基于CORDIC算法建立了FIR和IIR数字滤波器的电路模型，使之能在同一电路上通过开关控制集成实现。     

特种器件厚外延前后图形转移方法研究

提出了一种特种器件厚外延前后图形的转移方法.通过设计一块带外延前图形层的对位标记和投影光刻机识别标记的掩膜版,解决了厚外延之前图形的精确套准和厚外延之后投影光刻的难题,实现了厚外延前后的套刻精度高于0.5 μm.该方法可广泛应用于带埋层的VDMOS、超结VDMOS、高压互补双极器件,以及高压BCD器件的投影光刻.     

基于SOPC的呼吸音检测系统分析

文章介绍了一套由SOPC开发平台DE2实现的呼吸音检测系统,该平台核心为Altera的FPGA及内嵌的软核NIOSⅡCPU。该系统以24位音频编解码芯片WM8731进行呼吸音的采集与回放,利用短时能量、短时过零率以及时自相关分析确定呼吸音的起止,然后利用数字滤波器、FFT变换、线性预测分析等技术提取呼吸音相关参数,并用DTW算法进行综合匹配进行识别。实验结果表明,该系统可以高效识别多种呼吸音。     

基于Gabor滤波器和局部纹理特征提取的SAR目标识别算法

该文提出了一种基于Gabor滤波器和Three-Patch Local Binary Patterns(TPLBP)局部纹理特征提取的合成孔径雷达(Synthetic Aperture Rader, SAR)图像目标识别算法。首先, 利用Gabor滤波器对SAR图像在不同方向上进行滤波, 增强SAR图像中目标及其阴影的关键特征;然后, 利用TPLBP算法对Gabor滤波之后的图像进行局部纹理特征提取, 该算法克服了Local Binary Patterns(LBP)算法无法描述大范围领域纹理特征的缺陷, 并且保持了LBP旋转不变的特性, 减少了SAR图像目标方位变化对识别效果的影响;最后利用极限学习机(Extreme Learning Machine, ELM)分类器实现目标识别。该文通过MSTAR数据库中的3类SAR目标识别实验验证了该算法的有效性。      

旋转不变的三维物体识别

提出一种具有旋转不变性的三维物体识别的新方法。该方法通过结构照明的方法,使物体的高度分布以变形条纹的形式编码于二维强度像中。由于条纹图像包含有物体的高度分布信息,因而对条纹图的相关识别具有本征三维识别的特点。旋转不变性是通过使用多通道滤波器实现的,此滤波器可以由不同方向三维物体对应的变形条纹图像经计算机处理得到。相关识别方法可以用光学匹配空间滤波器实现。计算机模拟实验证明了这种方法的有效性,它不仅可以实现旋转不变的三维物体识别,还可以给出物体旋转角度的估计值。     

光瞳滤波投影光刻实验研究

介绍了一套自行研制的用于光瞳滤波实验的投影光刻实验系统，其物镜光瞳处预留出放滤波器的位置，可方便取放滤波器。在理论分析的基础上，开展了光刻对比实验研究，实验研究，实验研究结果表明光瞳滤波能大幅度提高投影光刻成像系统分辨力，并增大焦深，是一种比较有效地提高投影光刻成像质量的方法。     

远距离复杂背景鲁棒的步态特征提取与表示方法

远距离复杂背景下步态图像通常受到噪声的影响很大。Gabor特征在此类步态识别中显示了良好的特性,然而一些基于Gabor特征的算法使用较多的模板从而导致计算量增大。为解决这个问题,本文提出了一种新的基于改进Gabor特征的步态特征提取与表示方法。首先突出步态能量图中的有效区域,并抑制易受噪声干扰的区域。然后构造一个同时具有两个方向互补特性的基本的滤波器,经过缩放和旋转,生成一系列滤波器。使用这些滤波器对改进的步态能量图以及步态差异图像进行卷积,得到两个特征向量集合以表示此步态对象。使用最近邻分类计算出本文方法在USF步态数据库上的识别率,与相关算法的比较证实了此步态特征提取与表示方法的有效性。对算法的计算量分析表明,本文算法所需的计算量比相关算法有较大降低。      

一种采用双面对准的硅LIGA掩模制作研究

深Ｘ射线光刻是制作高深宽比ＭＥＭＳ结构的一个重要的方法。提出一种基于硅工艺和双面对准技术的ＬＩＧＡ掩模技术,工艺十分简单。采用该掩模,可进一步解决深Ｘ射线光刻中的重复对准多次曝光问题,给出了该掩模设计制作工艺过程及深Ｘ射线光刻结果,整个过程包括常常氮化夺、采用Ｋａｒｌ Ｓｕｓｓ双面对准曝光机进行ＵＶ光刻、电化学沉积金吸收体、体硅腐蚀形成支撑等。利用该掩模在北京ＢＥＰＣ的Ｘ射线光刻光束线上进行曝光。     

Capillary Force Lithography: Fabrication of Functional Polymer Templates as Versatile Tools for Nanolithography

The implementation of high‐resolution polymer templates fabricated by capillary force lithography (CFL) is explored both in nanoimprint lithography (NIL) and in the wet‐etching of metals. Several different thermoplastic and UV‐curable polymers and types of substrates are incorporated into the general CFL procedure to meet the diverging requirements of these two applications. The mechanical stability of UV‐curable templates for imprinting in polymers, as examined by atomic force microscopy (AFM), and their anti‐adhesive properties are excellent for application in NIL. The conditions for curing the UV‐curable polymer are optimized in order to obtain high‐stability polymer templates. Gold patterns on silicon with a lateral resolution of 150 nm are fabricated by subsequent lift‐off in acetone. Similar patterns with a lateral resolution of 100 nm are fabricated using templates of thermoplastic polymers on gold layers on silicon as an etch mask. The transfer of stamp residues during CFL with these polymer templates is proven by X‐ray photoelectron spectroscopy (XPS) and AFM friction analysis. For poly(methylmethacrylate) (PMMA), the presence of large amounts of silicon‐containing residues is found to compromise the processability of the resulting template in subsequent O₂ reactive‐ion etching (RIE) treatment. The extent of silicon contamination is up to six times less for polystyrene (PS). At this level, the etch performance of the PS etch mask is not affected, as was the case for PMMA. Accurate downscaling of the lateral dimensions of the resulting metal patterns by several factors with respect to the dimensions of the PS etch mask is achieved by over‐etching of the gold. Overall, the results in this paper demonstrate the potential of CFL templates as tools for high‐resolution soft lithography.     

A maskless laser-write lithography processing of thin-film transistors on a hemispherical surface

We report on the design and fabrication methods for a hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) on a non-planar substrate using laser-write lithography (LWL). Level-to-level alignment with a high accuracy is demonstrated using LWL method. The fabricated a-Si:H TFT exhibits a field-effect mobility of 0.27 cm²/V s, threshold voltage of 4.9 V and on/off current ratio of ∼6 × 10⁶ in a saturation regime. The obtained results demonstrate that it is possible to fabricate the a-Si:H TFTs and complex circuitry on a curved surface, using a well-established a-Si:H TFT technology in combination with the maskless lithography, for hemispherical or non-planar sensor arrays.     

一种数字光栅无掩模光刻对准方法

针对数字微反射镜装置(DMD)无掩模光刻系统,提出并研究了一种数字光栅无掩模光刻对准方法,将硅片的微位移放大显示在数字光栅与硅片物理光栅叠加产生的叠栅条纹中。建立了基于DMD的数字光栅无掩模光刻对准模型,设计了对准标记以及具体的实现方案,并对模型进行了数值仿真和初步的实验验证。结果表明,采用频率可变、图像干净、具有良好周期性结构的数字光栅代替传统的真实掩模光栅,真正实现了零掩模成本;并且采用变频率数字光栅可以扩大测量范围,减小位移测量误差。最终可以实现深亚微米的对准精度,满足目前无掩模光刻对准精度的要求。     

衍射干涉光刻研究

光刻就是将掩模版上的图形转移到基底的过程,广泛应用于微电子、微机械领域。衍射现象是光刻工艺无法避免的问题,当掩模图形尺寸接近光源波长时,就会产生衍射干涉现象。利用这一现象,可以产生小于掩模图形尺寸的图形。采用严格耦合波分析算法对光刻过程中的衍射干涉做了仿真分析;并用karl suss MA6光刻机实现了基于掩模的干涉光刻实验,通过增加滤光片得到相干光源,增强光刻过程的衍射,形成衍射干涉,掩模版透光区域和部分不透光区域下方的光刻胶得到曝光,利用微米尺度的光栅图形,在光刻胶上产生亚微米的光栅;最后利用干法刻蚀工艺,在硅基底上加工出亚微米尺度光栅。     

Aligned double exposure in deep X-ray lithography

Deep X-ray lithography with synchrotron radiation is a powerful tool to generate threedimensional microstructures with high aspect ratios. In order to complement and enhance the normal shadow printing with methods to generate true threedimensional structures, we investigated the aligned multiple exposure process to produce step-like LIGA structures also involving the sacrificial layer technique to obtain movable structures. Irradiations have been performed utilizing a newly developed X-ray Scanner (JENOPTIK GmbH) with internal optical alignment system.

Multiple exposure requires the alignment of mask and substrate. We used silicon nitride mask membranes with 10 μm thick gold absorber patterns, which show excellent transmission in the visible light range for alignment purposes and good X-ray transparency in the hard X-ray regime.

The first results of double exposure experiments obtained with the scanner prototype are promising. With the exception of a systematic error an alignment accuracy of σ_x = 0.26 μm and σ_y = 0.4 μm (standard deviation) has been achieved. Present work concentrates on the improvement of the adjustment system.

All the exposures have been carried out at the BESSY wavelength shifter (Berlin/Germany).     

高数值孔径光刻中衬底反射率的控制

高数值孔径（NA）光刻中,需要控制衬底反射率以减小薄膜干涉对光刻性能的影响。采用薄膜光学方法研究了高NA光刻中底层抗反膜（BARC）对衬底反射率的控制。针对硅基底对单层和双层BARC进行优化以探索满足高NA光刻要求的BARC材料光学参数容限。结果表明,当NA超过0.8时,单层BARC无法控制衬底反射率而有必要采用双层BARC。横电（TE）比横磁（TM）偏振光的衬底反射率更难以控制。NA越大,单层BARC折射系数的优化值越大。双层BARC中的顶层膜应采用低吸收率材料而底层膜应采用高吸收率材料。本研究可为高NA光刻中的BARC材料研制及衬底反射率控制提供理论依据。     

Fast patterning and dry-etch of SiNχ for high resolution nanoimprint templates

We developed a simplified nanofabrication process for imprint templates by fast speed electron beam lithography (EBL) and a dry etch technique on a SiNx substrate, intended for large area manufacturing. To this end,the highly sensitive chemically amplified resist (CAR), NEB-22, with negative tone was used. The EBL process first defines the template pattern in NEB-22, which is then directly used as an etching mask in the subsequent reactive ion etching (RIE) on the SiNx to form the desired templates. The properties of both e-beam lithography and dry etch of NEB-22 were carefully studied, indicating significant advantages of this process with some drawbacks compared to when Cr was used as an etching mask. Nevertheless, our results open up a good opportunity to fabricate high resolution imprint templates with the prospect of wafer scale manufacturing.     

用于传感的聚合物微谐振环的研制

对一种用于传感的聚合物微谐振环进行了研制.器件为多模耦合器结构,作为微谐振环的输入/输出耦合结构.微谐振环采用跑道形结构.首先分析了器件的原理,给出了器件的优化设计参数.采用紫外光敏材料SU-8和CYTOP作为波导芯层和下包层材料,制作了上述结构的微谐振环器件,并进行了测试.扫描电镜的结果显示,所制备器件的整体形貌比较清晰,波导结构均匀光滑,侧壁陡直度较高.采用截断法测得单模直波导的传输损耗约为2.2 dBcm.对多模耦合器(MMI)结构和弯曲波导的测试表明,MMI结构在较宽的波长范围内实现了接近50:50的功分比,且损耗较低,而纯弯曲波导结构的通光性能良好.测量得到的器件谐振输出光谱表明,器件在主谐振峰处的插入损耗约为38dB,自由光谱区(FSR)约为1.87nm.过数据处理分析得到弯曲波导的传输损耗约为5.2 dB/cm.提出了进一步降低器件损耗、改善器件性能的措施.     

Submicrometer CMOS device fabrication using an X-ray stepper

CMOS devices with submicrometer minimum features have been fabricated using X-ray/photo hybrid lithography. The device fabrication process utilized thirteen lithography steps, including four X-ray lithography levels, such as local oxidation of silicon (LOCOS) [1], gate, contact, and wiring, that required the most critical dimension control and alignment accuracy. A step and repeat exposure system and a SiNxmembrane mask were used for the X-ray lithography process. The SiNxmembrane mask was improved in its flatness and effective contrast by employing a stress compensating structure and a secondary electron trapping film. As a result, CMOS devices with 0.4-µm effective channel length were fabricated using a single-layer resist process.