聚合物芯片复型模具的新型制作工艺研究

AZ4620是一种广泛应用于微系统制作的正性光刻胶。高温改性后的AZ4620在紫外曝光时光照部分不再发生光化学反应,基于这样的材料特性,以220℃高温硬烘30 min获得改性的无光敏性的光刻胶,通过Plasma氧刻蚀制作出底层结构,再在底层结构表面涂胶采用多次曝光和显影制作出具有三层微结构的光刻胶模具,利用模塑法制作聚合物PDMS芯片。对光刻胶高温硬固工艺进行分析,对产生回流、残余应力、气泡等问题进行理论分析和实验研究,优化了模具加工工艺。采用多次喷涂,Plasma氧处理改善浸润性,高温硬烘0.5℃/min的升温速率得到了质量较好的多层光刻胶模具,为利用正性厚胶制作多层微结构提供了新的方法。     

PDMS柔性衬底的制备及亲水性问题的研究

针对PDMS柔性衬底的疏水性问题,设计了利用等离子体和表面活性剂联合修饰的解决方法。首先介绍了PDMS柔性衬底的制备方法,制备完成后对其进行单一的氧等离子体处理,依次改变改性时间、射频功率及氧气流量等数值,实验完成后利用接触角测试仪测得接触角大小为84o。其次研究了氧等离子体及表面活性剂（SDS）联合修饰的方法,在进行氧等离子体处理时选取了合适的处理时间避免裂纹的出现,再利用SDS对PDMS表面进行处理,处理完测得接触角的大小为22o,并且在空气中静置一段时间之后接触角不会出现复原的现象。实验结果证明,联合修饰有效的提高了PDMS表面的亲水性。     

单晶硅微结构表面的制备及其减反射性能北大核心

利用聚苯乙烯胶体微球组装的单层胶体晶体阵列作为掩模板,分别采用反应离子刻蚀和等离子体刻蚀工艺在晶体硅表面构造出不同形态的微纳米结构,并研究不同刻蚀方法和不同刻蚀时间对微结构形态的影响作用。利用分光光度计测试得到微结构表面的反射光谱曲线。结果表明,在0.35-1.1μm太阳光有效吸收波段,单晶硅材料微结构表面的反射率显著降低,由于此时材料的透射率为零,材料在该波段的吸收得到有效增强。同时,具有规则微结构表面的减反射性能比无序微结构表面的减反射性能要更好一些。这为增强单晶硅对太阳能的有效吸收提供了一种简单可行的方法。     

飞秒激光双光子聚合构建水溶性石墨烯-光刻胶的3D微结构

通过将水溶性石墨烯掺入至光引发剂2-苄基-2-二甲基氨基-1-（4-吗啉苯基）丁酮和季戊四醇三丙烯酸酯混合而成的光刻胶中,利用飞秒激光双光子聚合技术制作一系列平面图案及三维立体结构。利用亲水角测试表征混合物的浸润性,激光透过深度测试表征混合物的穿透性。实验结果证明,掺杂有水溶性石墨烯的混合液与玻璃仍具有较强结合力和一定激光穿透性。最后利用拉曼成像与扫描电子显微镜表征平面图案及三维结构。证实使用去离子水作为分散液可以将水溶性石墨烯掺杂进微结构中,并且掺杂有水溶性石墨烯的微结构在机械性能上比纯光刻胶微结构,结构更稳定且形貌更统一。     

PET织物表面紫外激光辐照改性与等离子体改性的比较

分别对PET织物的紫外激光改性和等离子体改性进行了实验研究,并利用水滴扩散时间、水珠在织物表面的扩散形状两个参数来比较了两种方法的改性效果,还应用FTIR光谱以及SEM图像分析了这两种方法在织物表面引起的化学和物理变化.发现248 nm的紫外激光辐照使织物表面产生波浪状微观结构,改善了织物染色性能,但对于织物的亲水性却没有什么改进,而氧气等离子体作用于织物后,改善了织物的亲水性和染色性,四氟化碳等离子体作用于织物表面后,增加了织物的疏水性.最后我们分析了这两种不同改性效果的产生原因,比较了两种改性方法的优缺点,并展望了激光改性以及等离子体改性在纺织工业上的应用前景.(OE7)     

表面形貌特殊的碳纳米管薄膜及其场发射增强

采用磁控共溅射法在Si片表面镀NiTi膜作为碳纳米管生长的催化剂,制备出表面形貌特殊的碳纳米管薄膜,如"丘状"和"星状"的表面微结构。通过扫描电子显微镜对碳纳米管薄膜的形貌进行表征,采用二极管形式测试了碳纳米管薄膜的场发射性能。实验结果表明,这两种碳纳米管薄膜都具有优异的场发射性能,10μA/cm~2时的开启电场分别仅为1.02 V/μm和1.15 V/μm,在外加电场为2.4 V/μm时的电流密度分别达到4.32 mA/cm~2和6.88 mA/cm~2。通过场发射FN的曲线计算得到的场发射增强因子分别为10113和6840。这两种碳纳米管薄膜优异的场发射性能与其表面的微结构有关。表面的粗糙结构增强了部分碳纳米管的局域电场,易于发射电子。     

散热结构拓扑优化目标函数适用性讨论

利用光刻胶作刻蚀掩模对半导体样品进行感应耦合等离子体干法刻蚀时发现光刻胶掩模在刻蚀后表面出现凸起和孔洞等异常现象, 等离子体会透过部分孔洞对样品表面产生刻蚀损伤。利用探针式表面轮廓仪和激光共聚焦显微镜对这些异常现象进行了分析, 认为是刻蚀时等离子体气氛中的紫外线对作为掩模的光刻胶进行了曝光作用而释放出一定量的氮气, 从而在光刻胶内外形成了压强差而使光刻胶局部表面产生微凸起; 当光刻胶的强度无法阻止内部氮气的膨胀时, 则会发生类似爆炸的效果, 在光刻胶表面形成孔洞状缺陷, 导致掩模保护作用的失效。     

感应耦合等离子体干法刻蚀中光刻胶掩模的异常性

利用光刻胶作刻蚀掩模对半导体样品进行感应耦合等离子体干法刻蚀时发现光刻胶掩模在刻蚀后表面出现凸起和孔洞等异常现象,等离子体会透过部分孔洞对样品表面产生刻蚀损伤.利用探针式表面轮廓仪和激光共聚焦显微镜对这些异常现象进行了分析,认为是刻蚀时等离子体气氛中的紫外线对作为掩模的光刻胶进行了曝光作用而释放出一定量的氮气,从而在光刻胶内外形成了压强差而使光刻胶局部表面产生微凸起;当光刻胶的强度无法阻止内部氮气的膨胀时,则会发生类似爆炸的效果,在光刻胶表面形成孔洞状缺陷,导致掩模保护作用的失效.     

SU-8胶光刻工艺参数优化研究

对基于SU-8胶的UV-LIGA技术进行了工艺优化,研究了光源波长和曝光时间对SU-8胶成型的影响。结果表明,光刻胶表面线宽变化随曝光时间增加先减少后增加,有一个极小值;侧壁角度先增加后减少,有一个极大值。通过优化光源波长、曝光时间以及显影时间三个主要工艺参数,可以获得侧壁角度为90.64°正角的300μm厚光刻胶微结构和侧壁角度为89.98°近似垂直的500μm厚光刻胶微结构。     

纳秒激光诱导氧化钛片及涂层的润湿性研究

采用纳秒激光在纯钛片表面制备微织构,并辅助化学处理的方法,获得了类似"荷叶效应"且润湿稳定的超疏水表面。通过调整激光加工工艺参数,获得了具有不同润湿性的微纳米结构;在此基础上,采用全氟癸基三甲氧基硅烷和乙醇溶液的混合溶液在微结构表面制备涂层。采用扫描电子显微镜和能谱分析后可知钛板在激光作用下产生了多尺度的氧化钛多孔微结构;通过接触角测量表征进一步分析了钛片表面的亲水性与微纳米结构表面变化规律的关系,以及涂层对表面润湿性的影响,为生物医学药物输送方面的研究提供了参考。     

电镀工艺主要参数对氨基磺酸镍镀层的影响

氨基磺酸镍由于沉积速度快,内应力低的特点,在电镀中得到广泛应用,为了解不同工艺参数对氨基磺酸镍镀层的影响,对电镀过程中的各个工艺参数进行了分析实验,得出了电导率、搅拌、电流密度、温度、pH和溶液中Ni＋2浓度、氯化物含量对电镀镍镀层质量的影响。     

The effect of gold-nickel metallization microstructure on fluxless soldering

Gold plating is used in the microelectronics industry to maintain the wettability of metal substrates. The nature of wetting during soldering of gold plated metals is discussed, and the results of experiments on the fluxless wettability and oxidation of gold plated nickel are described. The results suggest that electrodeposition of a thin gold plate (0.14 (xm) and the concurrent reduction of nickel oxide produce a gold-nickel system which will wet without flux. Oxidation of nickel was observed to occur via nickel out-diffusion and by direct exposure of the substrate through pinhole plating defects. Auger chemical analysis indicates that pinholes do not produce oxidation of the surrounding substrate area.     

碳酸镍沉淀过程的研究以及介孔氧化镍的制备

Nickel carbonate and nickel oxide are important inorganic fine chemicals, widely used in chemical, metallurgical, electronic and energy sources industries. The research was beginning with studying the effects of anions on precipitation process of nickel carbonate. Activity coefficient shows the effect size of the microcosmic effects between ions and solvent. Meissner's semi empirical model was applied to calculate the average activity coefficients of nickel carbonate in different electrolyte solutions at different conditions. And the conditional solubility of nickel carbonate was also calculated. The calculated results show that activity coefficients of NiCO3 in sodium sulphate solutions are less than that in sodium chloride solutions, and the solubilities in sodium sulphate solutions are larger. To improve the confidence of the calculations, Bromley's and Pitzer's models were also applied to calculate activity coefficients. The calculation results of Bromley's and Pitzer's models are very close to Meissner's results. And then experiments were carried out to measure the surface tensions, and contact angles of solutions on NiCO3 surface. According to the experiment results, the solid-liquid interface tension between NiCO3 and sodium sulphate solution is larger than that between NiCO3 and sodium chloride solution. And the tiny crystal NiCO3 has larger solubility in sodium sulphate solutions, which indicates that crystallization of NiCO3 in sodium sulphate solution is more difficult than in sodium chloride solution. The influence of SO 42- and Cl- on precipitation and crystallization process of NiCO3 was also studied based on crystal dynamics. The supersaturations at different initial concentration of reaction system were compared. Diffusion coefficients of ions were described by Glasstone's model. The diffusion coefficients of Ni2+ and CO 32- in chloride solutions are larger than those in sulphate solutions. In sulphate solutions, the diffusion coefficients and supersaturation are both less, therefore nucleation and growth rates are more slowly. Furthermore, the experiments of crystallization dynamics show that the reaction of nickel carbonate precipitation is a first order reaction while the reaction rate constant is about 0.02 min-1. Based on the theoretical analysis above, technology process of nickel carbonate precipitation was studied subsequently. The effects of nickel salt, feeding mode, controlling pH, reaction temperature and aging condition on purity, particle size, appearance of product and recovery ratio of nickel were investigated. Then using industrial nickel electrolyte solution and sodium carbonate as the raw materials, nickel carbonate product with nickel content of about 51%,average particle size of 17 μm was prepared at optimal conditions, and the recovery ratio of nickel is around 99.5%. Nickel carbonate with high purity was obtained via an innovative impurity removal process, called wash-dry-rewash-redry process. The sodium and chlorine qualitative contents of the nickel carbonate purified by the innovative method are both less than 0.01% and the sulphate content is no more than 0.1%. The mechanism of sodium and chlorine adsorption onto nickel carbonate's surface was discussed, using Stern's model of electric double layer. Moreover computational simulation technology was applied to investigate on how anions affect the crystallization of NiCO3 at atom scale. The lattice structure was relaxed before establishing crystal surfaces. The computational unit cell parameters are very close to the experimental data. Five main surfaces were studied, i.e. the (104), (100), (110), (001) and (101) surfaces. SO 42- substitutes the CO 32- on the outmost layer. Cl- adsorbs onto the surfaces and has relative weaker interaction with the surfaces. Compared with only hydrated surfaces, the growth rates of defected hydrated surfaces significantly decrease, especially for SO 24- defected ones. The (104) surface is the most stable surface and is mainly expressed in the equilibrium morphology of the resulting crystal. Finally, based on the study of nickel carbonate synthesis, nickel oxide with mesoporous structure was prepared by adding template into the nickel source and calcination. The effects of types of surfactant, dosage of surfactant, calcination temperature and calcination time on pore structure and specific surface area of nickel oxide were investigated. The results show that the surface area of the nickel oxide prepared by sodium dodecyl sulphate (SDS, anion surfactant) is much larger than those of which prepared by CTAB and octadecylamine. It is suggested that the inorganic species, basic nickel carbonate, is interacted with the template, SDS, by electrostatic attraction force. The precursor hardly has any surfactant residue after calcination. Nickel oxide with high specific surface area (>200 m2· g-1) is synthesized by adding low amount of template at the mole ratio of SDS:Ni less than 0.1:1.0. The nickel oxide has H3 type hysteresis and the pore size distribution mainly ranges from 2 nm to 10 nm. And it has good thermal stability.     

高可靠镀Ni／Au工艺及其在微波PTFE电路上的应用

介绍了高可靠电镀Ｎｉ／Ａｕ工艺在ＰＴＦＥ微波印制电路上的应用，并分析了氨基磺酸盐镀软镍和亚硫酸盐镀软金工艺的影响因素及提高Ｎｉ／Ａｕ镀层之间附着力的措施。通过实验及应用证明了与直接镀金工艺相比，在软基材ＰＴＦＥ敷铜箔板上镀Ｎｉ／Ａｕ工艺能大大提高微波电路的可焊性，高温稳定性和长期可靠性，并且用其所制作的微波器件的高频性能也优于直接镀金工业。     

氧等离子体处理改善ITO电极表面湿润性

采用氧等离子体处理对有机发光器件ITO电极进行表面改性,基于接触角的测量,利用几何平均法计算了ITO的表面能和极性度,研究了氧等离子体处理对ITO电极表面湿润性的影响.实验数据和计算结果表明:氧等离子体处理后,ITO表面极性度增加,表面能增大,接触角减小,其表面湿润性得到很大改善.同时,进一步研究了氧等离子体处理对有机发光器件性能的影响,结果显示:ITO电极表面湿润性的改善,提高了发光亮度和效率,降低了启亮电压和驱动电压,有效地改善了器件的光电性能.     

AlN陶瓷表面化学镀镍工艺

采用化学镀镍的方法对AlN陶瓷进行金属化。研究了陶瓷表面粗化工艺、化学镀溶液成分等对镀层的影响,得到了最佳工艺：采用500 g.L-1的NaOH溶液对AlN陶瓷进行30 min腐蚀粗化,可得到理想的粗化表面;采用的十二烷基硫酸钠作为镀液表面活性剂,浓度为100 mg.L-1,可减少镀层中的氢含量,使得镀层更加致密。将金属化后的AlN陶瓷与SiCp/Al复合材料焊接,剪切强度可达到110 MPa。     

Effect of Thickness and Phosphorus Content on Au/Pd/Ni(P) Metal Finish of Printed Circuit Board

Electroless nickel/electroless palladium/immersion gold [Au/Pd/Ni(P) or ENEPIG] pads consisting of layers of Ni(P) (200 μin), pure palladium (Pd) or palladium phosphorus (PdP) (2 μin, 4 μin or 6 μin), and gold (Au) (2 μin or 4 μin) were prepared using two different processes (wire bonding and lead-free soldering). Each of these processes was done with zero- or two-time reflow. Different tests on solderability, wettability, wire-bonding capacity, and corrosion resistance were performed on different combinations of ENEPIG pads formed using different combinations of processes and conditions. Scanning electron microscopy was also performed to examine the surface characteristics of the pads. It was found that the ENEPIG pad sample with the 4-μin-thick Au and 4-μin-thick PdP layers possessed stable wire-bonding capacity and excellent lead-free solder reliability. In addition, the ENEPIG–PdP systems showed better corrosion resistance, which is attributed to the presence of the amorphous PdP layer protecting the nickel layer.     

微电子封装无铅焊料润湿性研究

为解决无铅焊料润湿性差的问题,采用卤化物活性剂松香焊剂,通过实验研究了Sn-9Zn焊料的润湿性。分析讨论了影响Sn-9Zn焊料润湿性的因素,获得了最佳匹配。在镀锡铜片上,有机卤化物+无机卤化物活性剂松香焊剂(#6焊剂)匹配Sn-9Zn焊料获得最佳的润湿性(润湿角为12°),接近Sn-37Pb焊料的润湿性。     

稀土改性的Sn-58Bi低温无铅钎料

研究了微量稀土对Sn-58Bi低温钎料的改性作用.试验添加质量分数为0.1 ?组混合稀土的无铅材料,并对比Sn-58Bi和Sn-58Bi0.5Ag合金.观察了钎料显微组织的变化并做了定量分析,采用DSC测试了钎料的熔化温度,同时测量了钎料的润湿性能、接头强度与硬度.结果表明,微量稀土添加细化了Sn-58Bi钎料合金的显微组织,对钎料的熔化温度几乎没有影响,能显著改善Sn-58Bi钎料的润湿性能和接头剪切强度,而且改善的程度优于添加微量Ag对Sn-58Bi钎料的作用.     

飞秒激光制备PMMA表面微结构的作用机理和润湿性研究

采用飞秒激光微加工技术对聚甲基丙烯酸甲酯(PMMA)表面进行微加工,研究PMMA表面不同微结构的润湿性。首先对飞秒激光去除透明聚合物材料的机理进行研究并建立了材料去除模型,制备出PMMA表面光栅结构和方柱结构;采用超景深三维显微镜和接触角测量仪对微结构表面形貌和润湿性进行测量分析。结果表明:飞秒激光加工PMMA表面微结构可以将PMMA润湿性从亲水向疏水状态转变,微结构间距过小会导致激光加工时飞溅的熔融物堆积在结构通道。