基于分步式压印光刻的激光干涉仪纳米级测量及误差研究

针对在未做隔离保护处理的环境中,基于Michelson干涉原理的激光干涉仪测量系统存在严重的干扰误差,不适合分步式压印光刻纳米级对准测量的要求.采用Edlen公式的分析及计算,不仅在理论上揭示出环境温度、湿度、气压等变化对激光干涉仪测量准确度的影响,而且证明影响测量准确度的最大干扰源是空气流动的结果.通过气流隔离措施和系统测量反馈校正控制器,能够实时补偿激光干涉仪两路信号的相差.最终,测量漂移误差在10 min内由13 nm降低到5 nm以内,满足压印光刻在100 mm行程中达到20 nm定位准确度要求.     

基于中心-射线模型的印鉴识别方法及其应用

支票中的有效印鉴是支票流通有效性的重要体现。通过对支票印鉴有效性的识别来达到对支票流通有效性识别的目的。根据我国支票图像的特点提出了基于中心_射线模型的有效印鉴识别方法。该方法是通过对印鉴各成份区域之间拓扑关系的识别来达到对有效印鉴识别的目的。在将该方法用于我国支票印鉴识别的同时,还利用了印鉴的色彩特征。实验结果表明,该方法可有效地识别我国支票中的有效印鉴,有效印鉴识别的错误排除率为0%,错误接收率为23.8%。     

Synthesis and characterization of hyperbranched polymers with increased chemical versatility for imprint lithographic resists

Hyperbranched polymers were prepared from a variety of mono‐ and difunctional monomers and used in the development of novel UV‐imprint lithography (UV‐IL) resists. The unique physical and chemical properties of these hyperbranched materials significantly increase the range of molecular systems that could be imprinted. Traditional challenges, such as the use of monomers that have low boiling points or the use of insoluble/highly crystalline momomers, are overcome by the preparation of hyperbranched polymers that incorporate these repeat units. In addition, the low viscosity of the hyperbranched macromolecules and the large number of reactive chain ends overcome many difficulties that are traditionally associated with the use of polymeric materials as imprint resists. Hyperbranched polymers containing up to 12 mol % pendant vinyl groups, needed for secondary crosslinking during imprinting, were prepared with a wide range of repeat unit structures and successfully imprinted with features from tens of microns to ∼ 100 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6238–6254, 2008     

胆红素分子表面印迹材料MIP-PMAA/SiO2的制备及识别特性

通过γ-（甲基丙烯酰氧）丙基三甲氧基硅烷的媒介作用,在硅胶微粒表面偶合接枝聚甲基丙烯酸（PMAA）,制备了PMAA/SiO2接枝微粒。采用新型分子表面印迹技术,以乙二醇二缩水甘油醚（EGDE）为交联剂,制备了以胆红素为模板分子的表面印迹材料MIP-PMAA/SiO2。分别通过静态和动态吸附实验考查了该印迹材料对胆红素的识别特性。结果表明：该印迹材料对胆红素兼具优良的结合亲和性和特异的识别选择性,同时,具有优良的脱附性能,脱附率可达99.5%。     

Synergistic effects of total ionizing dose on single event upset sensitivity in static random access memory under proton irradiation

Nitrogen plasma passivation （NPP） on （111） germanium （Ge） was studied in terms of the interface trap density, roughness, and interfacial layer thickness using plasma-enhanced chemical vapor deposition （PECVD）. The results show that NPP not only reduces the interface states, but also improves the surface roughness of Ge, which is beneficial for suppressing the channel scattering at both low and high field regions of Ge MOSFETs. However, the interracial layer thickness is also increased by the NPP treatment, which will impact the equivalent oxide thickness （EOT） scaling and thus degrade the device performance gain from the improvement of the surface morphology and the interface passivation. To obtain better device performance of Ge MOSFETs, suppressing the interfacial layer regrowth as well as a trade-off with reducing the interface states and roughness should be considered carefully when using the NPP process.     

The role of experimental science in ICF – examples from X-ray diagnostics and targets

The USA Inertial Confinement Fusion (ICF) Program evolved from the Nuclear Test Program which had restricted shot opportunities for experimentalists to develop sophisticated experimental techniques. In contrast the ICF program in the US was able to increase the shot availability on its large facilities, and develop sophisticated targets and diagnostics to measure and understand the properties of the high energy density plasmas (HEDP) formed. Illustrative aspects of this evolution at Lawrence Livermore National Laboratory (LLNL), with examples of the development of diagnostics and target fabrication are described.     

The fabrication of 3-D nanostructures by a low- voltage EBL

Three-dimensional (3-D) structures are used in many applications, including the fabrication of opto-electronic and bio-MEMS devices. Among the various fabrication techniques available for 3-D structures, nano imprint lithography (NIL) is preferred for producing nanoscale 3-D patterns because of its simplicity, relatively short processing time, and high manufacturing precision. For efficient replication in NIL, a precise 3-D stamp must be used as an imprinting tool. Hence, we attempted the fabrication of original 3-D master molds by low-voltage electron beam lithography (EBL). We then fabricated polydimethylsiloxane (PDMS) stamps from the original 3-D mold via replica molding with ultrasonic vibration.First, we experimentally analyzed the characteristics of low-voltage EBL in terms of various parameters such as resist thickness, acceleration voltage, aperture size, and baking temperature. From these e-beam exposure experiments, we found that the exposure depth and width were almost saturated at 3 kV or lesser, even when the electron dosage was increased. This allowed for the fabrication of various stepped 3-D nanostructures at a low voltage. In addition, by using line-dose EBL, V-groove patterns could be fabricated on a cured electron resist (ER) at a low voltage and low baking temperature. Finally, the depth variation could be controlled to within 10 nm through superposition exposure at 1 kV. From these results, we determined the optimum electron beam exposure conditions for the fabrication of various 3-D structures on ERs by low-voltage EBL. We then fabricated PDMS stamps via the replica molding process.     

Fabrication and Manipulation of Magnetic Composite Particles with Specific Shape and Size

The fabrication of microscale polyethylene glycol diacrylate(PEGDA) hydrogel particles was demonstrated via magnetic property ultraviolet(UV) lithography techniques, polydimethylsiloxane(PDMS) soft stamp pre-paration techniques and micro-nano imprint technology in this paper. The results of compositional and morphological characterizations of magnetic microparticles show that the Fe₃O₄ nanoparticles with an average diameter of 100 nm are uniformly dispersed in hydrogel. Owing to the excellent magnetism of Fe₃O₄ nanoparticles, the fabricated hydrogel microparticles with different sizes and shapes were manipulated in water via applying an external magnetic fields. Three types of motions, translation, rotation and flip, were demonstrated with the manipulator. These microscale magnetic PEGDA hydrogel particles have a great application potential in manufacturing process, micro/nanomotors, and machines.     

2-异戊基环戊酮虚拟模板印迹微球的制备及其吸附性能

以2-异戊基环戊酮为虚拟模板,采用沉淀聚合法制备了粒径20~50 μm的分子印迹微球。 用傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)研究了分子印迹微球的表面化学特征及粒径分布,测试了印迹聚合物对玫瑰醚的吸附动力学、等温吸附性能及吸附选择性。 考察了分子印迹固相萃取玫瑰醚的应用效能。 结果表明:分子印迹聚合物(MIPs)对玫瑰醚的吸附可在25 min达到平衡,具有较快的吸附动力学,一级动力学模型更适合描述其吸附动力学行为。 Freundlich模型最适合描述MIPs对玫瑰醚的等温吸附行为,聚合物材料最大的印迹位点数目为149.3 μmol/g。 聚合物对玫瑰醚的平均吸附能为166 kJ/mol,表明主要为化学吸附。 虚拟模板印迹聚合物对玫瑰醚的选择因子相对于香叶醇和香茅醇分别为3.710和5.636,且对含玫瑰醚的混合物中的目标化合物仍具有较高的选择吸附能力(竞争吸附量为18.02 mg/g)。 在优化洗涤(1 mL乙腈+1 mL乙腈和水混合溶剂(体积比9.5:0.5)+2 mL乙腈、甲醇和水混合溶剂(体积比8:1:2)和洗脱(3 mL甲醇和醋酸混合溶剂(体积比9:1))条件下,通过分子印迹固相萃取可实现玫瑰醚的有效分离和富集,回收率为96.23%。     

SiO2表面双酚A中空分子印迹纳米球的制备及识别性能

A novel and effective approach was developed to synthesize monodisperse hollow molecularly imprinted polymers (MHMIPs) with unfunctionalized SiO₂ spheres in a mixture of toluene and CH₃CN.The factors that affected the synthesis of MHMIPs were systematically investigated.It was determined that a suitable ratio of toluene to CH₃CN and the use of a functional monomer that can generate double H-bonding interactions were the critical factors to obtain MHMIPs with high uniformity and monodispersion.The obtained MHMIPs exhibited a fast adsorption rate and high adsorption capacity (270 μmol/g) for bisphenol A.As the shell thickness increased from 90 nm to 130 nm,the binding capacity of the imprinted shells decreased gradually.The relative selectivity coefficients of MHMIPs for tetra-bromobisphenol A (TBBPA),phenol and p-tert-butylphenol (PTBP) were calculated as 1.53,1.83 and 1.90,respectively.These findings indicate that MHMIPs have good adsorption performances and suggest applications in the selective removal or sensitive analysis of bisphenol A.