应用三维线算法的SU-8胶光刻过程模拟

采用二维法向量作为分量,加权求和近似得到三维网格点上的单位法向量,将经典的二维线算法改进为三维形式。综合SU-8胶光刻过程中衍射、吸收率随光刻胶深度的变化及交联显影等各种效应,应用该三维线算法对SU-8化学放大胶进行光刻过程三维建模。该模型对被加工表面演化过程的模拟较为精确,可在实际应用中对SU-8胶的光刻模拟结果进行有效预测。     

SU-8胶深紫外光刻模拟

综合了SU-8胶光刻过程中衍射、反射、折射、吸收率随光刻胶深度的变化及交联显影等各种效应,考虑了折射及吸收系数随时间的变化,建立了SU-8化学放大胶的光刻模型.模拟结果显示,该模型比现有的模拟方法结果更精确,与实验结果符合较好,可以在实际应用中对SU-8光刻胶的二维模拟结果进行有效预测.     

SU-8胶深紫外光刻模拟

综合了SU-8胶光刻过程中衍射、反射、折射、吸收率随光刻胶深度的变化及交联显影等各种效应,考虑了折射及吸收系数随时间的变化,建立了SU-8化学放大胶的光刻模型.模拟结果显示,该模型比现有的模拟方法结果更精确,与实验结果符合较好,可以在实际应用中对SU-8光刻胶的二维模拟结果进行有效预测.     

SU-8胶与基底结合特性的实验研究

SU-8胶是一种负性、环氧树脂型、近紫外线光刻胶。它适于制作超厚、高深宽比的MEMS微结构。为电铸造出金属微结构，通常需要采用金属基底。但SU-8胶对金属基底的结合力通常不好，因而限制了其深宽比的提高。从SU-8胶与基底的浸润性、基底表面粗糙度以及基底对近光紫外光的折射特性入手，对SU-8胶与基底的结合力进行分析，首次指出：在近紫外光的折射率高的基底与SU-8胶有很好的结合性。经实验得出经过氧化处理的TI片的SU-8胶的结合性强。这有利于为MEMS提供低成本，高深宽比的金属微结构。     

紫外线厚胶光刻技术研究及应用

紫外线厚胶光刻技术已广泛应用于3D微机械结构的制作.本文选用AZ4620和SU-8两种光刻厚胶,采用德国卡尔*休斯公司的MA-6双面对准光刻机,对紫外线光刻工艺条件进行了对比研究,结果表明,负性光刻胶SU-8的光敏性好,胶结构图形的侧墙较陡直,能够实现较大的深宽比,为复杂结构的三维微机械器件的制作提供了保证.     

紫外线厚胶光刻技术研究及应用

紫外线厚胶光刻技术已广泛应用于3D微机械结构的制作.本文选用AZ4620和SU-8两种光刻厚胶,采用德国卡尔*休斯公司的MA-6双面对准光刻机,对紫外线光刻工艺条件进行了对比研究,结果表明,负性光刻胶SU-8的光敏性好,胶结构图形的侧墙较陡直,能够实现较大的深宽比,为复杂结构的三维微机械器件的制作提供了保证.     

SU-8胶曝光衍射效应的模拟及丙三醇补偿方法

基于SU-8胶的UV-LIGA技术是MEMS中制备高深宽比结构的一种重要方法,但由于衍射效应会使结构的侧壁不再垂直，根据菲涅耳衍射模型,考虑了丙三醇/SU-8界面的反射和折射现象,模拟了丙三醇填充在掩膜版和光刻胶之间时的刻蚀图形。计算结果与已有的实验进行了比较,模型基本可以描述这种光刻过程,可在设计时作为参考。     

SU-8胶曝光衍射效应的模拟及丙三醇补偿方法

基于SU-8胶的UV-LIGA技术是MEMS中制备高深宽比结构的一种重要方法,但由于衍射效应会使结构的侧壁不再垂直.根据菲涅耳衍射模型,考虑了丙三醇/SU-8界面的反射和折射现象,模拟了丙三醇填充在掩膜版和光刻胶之间时的刻蚀图形.计算结果与已有的实验进行了比较,模型基本可以描述这种光刻过程,可在设计时作为参考.     

SU-8环氧树脂的分离实验研究

为分析和解决商业用SU-8胶在355 nm波长的吸收性和后烘缩胶等问题,先采用柱层析对SU-8环氧树脂进行分离,然后进一步用高压液相色谱-尺寸排阻色谱法对SU-8环氧树脂进行分离和分析。结果表明,SU-8环氧树脂包括SU-1,SU-2,SU-4,SU-6和SU-8多种组分及其它杂质,分子量分布在100-100 000的范围。根据分析结果,研究了上述问题出现的原因,并配制了性能优化的SU-8光刻胶,结合全息光刻技术制作了三维光子晶体。     

基于UV-LIGA技术的双层微齿轮模具镶块工艺

以氧化铟锡(ITO)玻璃作为基底,采用UV-LIGA技术制作了双层微齿轮型腔模具的镶块。首先,采用正胶(RZJ-304)进行光刻,在ITO玻璃表面电镀镍掩模,通过镍掩模对第一层SU-8光刻胶进行背面曝光。再利用正面套刻的方法对第二层SU-8光刻胶进行曝光,显影得到双层微齿轮的胶模。最后,进行微电铸得到双层微齿轮型腔镶块。通过实验验证了双层微齿轮模具镶块制作的工艺流程,优化了其工艺参数,克服了底部曝光不足引起的问题,并对制作工艺过程中产生的涂胶不平整、前烘时胶层不稳定、热板加热不均以及接触式曝光破坏胶层表面等问题进行了研究。所制得的双层微齿轮胶模垂直度高,表面质量好,且套刻精度高。     

Bending characteristics of SU-8

This study characterises SU-8's material properties under large deformations in out-of-plane bending. A novel test setup is presented to deform the SU-8 to high levels, and a mathematical model presented that accurately predicts the results. This test shows that hard-baked SU-8, with a Young's modulus tested at 1.9 GPa, is capable of undergoing stresses of up to 120 MPa before failure and in some cases will undergo plastic deformation.     

Programmable Liquid Metal Microstructures for Multifunctional Soft Thermal Composites

Soft, elastically deformable composites can enable new generations of multifunctional materials for electronics, robotics, and reconfigurable structures. Liquid metal (LM) droplets dispersed in elastomer matrices represent an emerging material architecture that has shown unique combinations of soft mechanical response with exceptional electrical and thermal functionalities. These properties are strongly dependent on the material composition and microstructure. However, approaches to control LM microdroplet morphology to program mechanical and functional properties are lacking. Here, this limitation is overcome by thermo‐mechanically shaping LM droplets in soft composites to create programmable microstructures in stress‐free materials. This enables LM loadings up to 70% by volume with prescribed particle aspect ratios and orientation, enabling control of microstructure throughout the bulk of the material. Through this microstructural control in soft composites, a material which simultaneously achieves a thermal conductivity as high as 13.0 W m^?1 K^?1 (>70 × increase over polymer matrix) with low modulus (<1.0 MPa) and high stretchability (>750% strain) is demonstrated in stress‐free conditions. Such properties are required in applications that demand extreme mechanical flexibility with high thermal conductivity, which is demonstrated in soft electronics, wearable robotics, and electronics integrated into 3D printed materials.     

高膨胀系数玻璃-陶瓷复合材料的性能研究

选用具有良好介电性能和膨胀性能的硼硅酸盐(SiO2-BaO-B2O3-Al2O3)和石英,采用固相法合成了一系列具有高热膨胀系数的玻璃-陶瓷复合材料,并对这些复合材料进行了XRD、SEM分析,及其热、力、电性能的测试。结果表明:所制复合材料的热膨胀系数和弯曲强度随着石英含量的增加而增大,其相对介电常数则随之减小。石英质量分数为40%的复合材料在980℃烧结时,析出了大量的方石英相,复合材料的热膨胀系数增大。最终制备的复合材料具有高的热膨胀系数[(10.3～25.5)×10-6/℃]、较高的弯曲强度(146MPa)、较低的相对介电常数(5.6～6.4)及介电损耗(0.10%～0.30%)。     

Suspension of nanoparticles in SU-8: Processing and characterization of nanocomposite polymers

Composite materials consisting of polymers and nanoparticles can provide additional functionality to existing formulations. Diamondoids, single-wall carbon nanotubes (SWNT), and gold nanospheres were physically incorporated into the negative photoresist SU-8 to investigate their effects on residual stresses and introduce piezoresistivity. The mixtures were spin cast onto silicon or aluminum-coated silicon wafers, lithographically patterned and released from the substrate. The residual stresses, elastic moduli, and viscosity effects of the nanocomposites were measured and compared with those of control samples of SU-8. Electrical properties of SU-8/SWNT nanocomposites were also investigated. The effective elastic modulus of SU-8/diamantane samples remained approximately 1.5-1.6 GPa until the diamantane content exceeded 7 wt%. The viscosity of SU-8/diamantane nanocomposite samples of all tested weight percents decreased compared with control SU-8 at high shear rates (>20 Hz), though high weight percent solutions (>5%) had increased low-frequency viscosity. The effective elastic modulus of the SU-8/SWNT nanocomposites decreased with small wt% additions of SWNT. Additionally, SU-8/SWNT nanocomposites showed increased resistivity with increased strain, suggesting a gauge factor for the 1 wt% SU-8/SWNT nanocomposite of approximately 2-4.     

天然鲜胶乳制备蒙脱土/NR纳米复合材料的结构与性能

采用多溶剂分散法制备片层尺寸达微、纳米级蒙脱土,并与天然鲜胶乳混合制备蒙脱土/天然橡胶复合材料,用扫描电镜研究蒙脱土结构及其在复合材料中的分布,并测定其力学性能.结果表明,通过多溶剂分散法可制备片层厚度为100nm～200nm的蒙脱土;在蒙脱土填充量为7%时,复合材料500%定伸应力从6.96MPa提高到11.22MPa;加入2%蒙脱土,复合材料拉伸强度从17.71MPa提高到21.01MPa;在4%填充量下,拉伸强度达23.56MPa,体现蒙脱土纳米增强效应.材料扯断伸长率随蒙脱土填充量增加而下降的幅度小,复合材料保持高弹性.复合材料硬度在蒙脱土填充量为8%时达到稳定值.上述结果表明,天然鲜胶乳可与蒙脱土直接复合,制备高性能天然橡胶复合材料.     

激光沉积制备A15-Nb3Al/B2叠层金属间化合物复合材料

铌基金属间化合物是一种潜在高温结构材料,室温脆性大。用Nb-12Ti-22Al和Nb-40Ti-15Al两种混合粉末,经激光沉积分别合成制备了A15-Nb3Al金属间化合物脆性涂层和韧性B2结构合金涂层。通过对制备工艺的研究,基本实现了每层成分和层厚的控制,利用韧脆相间层层叠加方法用激光制备出不同层厚比的脆韧相间A15-Nb3Al/B2叠层结构金属间化合物基复合材料。叠层复合材料的元素成分、显微组织和显微硬度均呈周期性变化,界面存在渐变过渡。叠层结构Nb基金属间化合物复合材料具有良好的室温和高温强度,性能呈各向异性。随着脆韧层厚比的增大,叠层复合材料的强度增加,在水平、竖直两方向的室温屈服强度最高分别可达1030 MPa和871 MPa,900℃屈服强度最高分别为301 MPa和267 MPa。     

Strong,Tough, Electrospun Polymer–Nanotube Composite Membranes with Extremely Low Density

Electrospinning has been used to produce porous, low density, polymer–nanotube composite membranes. The membrane mechanical properties can be enhanced by tuning the nanotube content, aligning the fibers during spinning, and by post production drawing. The mechanical properties are maximized for membranes with a nanotube content of 0.43 vol %. Aligned composites at this volume fraction have been prepared by spinning onto a rotating drum collector electrode. This method results in significant increases in modulus, strength, and toughness. The best composites, produced at the maximum drum rotation rate, were post treated by a drawing step to result in further increases in modulus and strength. These methods allows the production of membranes with densities as low as ～340 kg m^?3 but with values of stiffness, strengths and toughness's more typically found in bulk thermoplastics; 1.2 GPa, 40 MPa, and 13 J g^?1.     

质子交换膜燃料电池的垫片机械性能研究

为了将石墨复合材料用于燃料电池的双极板材料中,研究了湿度环境对双极板力学性能的影响。制造了两种类型的样品,对两种样品进行了一系列的实验：吸水率、弯曲和拉伸试验的强度和模量。结果表明,添加石墨复合材料的试样吸水率低于没有石墨/环氧复合材料碳纤维织物的试样,所以有碳纤维织物试样的总吸水率较低。两种试样的弯曲强度和模量均会下降。另外在石墨-颗粒/环氧复合材料中加入碳纤维织物能够显著提高了拉伸强度。     

Mechanical Properties of Robust Ultrathin Silk Fibroin Films

Robust ultrathin multilayer films of silk fibroin were fabricated by spin coating and spin‐assisted layer‐by‐layer assembly and their mechanical properties were studied both in tensile and compression modes for the first time. The ultrathin films were characterized by a high elastic modulus of 6–8 GPa (after treatment with methanol) with the ultimate tensile strength reaching 100 MPa. The superior toughness is also many times higher than that usually observed for conventional polymer composites (328 kJ m^–3 for the silk material studied here versus typical values of < 100 kJ m^–3). These outstanding properties are suggested to be caused by the gradual development of the self‐reinforcing microstructure of highly crystalline β‐sheets, serving as reinforcing fillers and physical crosslinks, a process that is well known for bulk silk materials but it is demonstrated here to occur in ultrathin films as well, despite their limited dimensions. However, the confined state within films thinner than the lengths of the extended domains causes a significantly reduced elasticity which should be considered in the design of nanosized films from silk materials. Such regenerated silk fibroin films with outstanding mechanical strength have potential applications in microscale biodevices, biocompatible implants, and synthetic coatings for artificial skin.     

ZnO对钙长石/莫来石复合材料性能的影响

以钙长石和莫来石等为主要原料,制备了与硅芯片相匹配的新型复合材料。研究了烧结助剂ZnO的加入量、烧结温度和显微结构等因素对材料性能的影响。结果表明:当w(ZnO)为8%时,该复合材料烧结温度为1000℃,其主要性能如下:在1MHz下εr为6.48,tanδ为4.00×10–3,抗折强度为76.29MPa,αl(25~500℃)为3.44×10–6℃–1。