硅片硬质抛光盘化学机械抛光工艺参数优化试验研究

在二氧化硅抛光液中加入聚合物微球,对硅片进行了复合粒子硬质抛光盘化学机械抛光试验.应用田口法对玻璃盘表面粗糙度、聚合物微球粒径、聚合物微球质量分数3个影响硅片材料去除率的因素进行了优化分析,得到以材料去除率为评价条件的最优抛光参数.对玻璃盘表面粗糙度和聚合物质量分数对硅片材料去除率的具体影响进行了实验分析,验证了上述结论.结果表明:玻璃盘的表面粗糙度与聚合物微球的粒径相适应和聚合物微球质量分数适中时,可以获得较高的抛光效率.     

科学家研发新型智能显示结构色薄膜材料

<正>复旦大学材料科学系教授武利民团队将直径为数微米至十几微米的聚合物胶体微球,组装到普通透明聚合物胶带的黏胶层上成单层微球阵列,首次研发了一种既具有逆反射又具有随角异色和随角不变色的智能响应结构色薄膜材料,并揭示了其智能响应结构色的形成机制。结构色相比于传统的化学色(如颜料、染料等着色)而言,具有色彩反射率高、饱和度高、不易褪色、环保等特点,但现有自然界或人工合成结构色材料均不具有智能响应特性。武利民团队发展出的大面积逆反射结构色薄     

软相尺寸对反贝壳复合材料压缩性能的影响

文章采用一步球磨结合真空热压工艺制备了由Al₂O₃/Al纳米复合材料(硬相)和纯铝(软相)构成的反贝壳结构复合材料,研究了软相尺寸(从微米级到亚微米级)对复合材料压缩性能的影响,并对其变形失效机制进行了分析。结果表明：在保持高失效应变的前提下,抗压强度随软相尺寸的减小而逐渐提高,尤其是从微米级减小到亚微米级时,抗压强度达到494 MPa,比微米级时至少提高60%;当软相尺寸为微米级时,复合材料中的裂纹萌生于软硬相界面处,并沿着界面-硬相-软相扩展,最终形成沿着与加载方向呈45°的宏观主裂纹。同时,软相可有效阻挡二次裂纹的扩展,当软相尺寸减小到亚微米级别时,裂纹萌生于软相变形带附近并沿着变形带-硬相扩展,逐渐演变成与加载方向呈±45°的均匀分散于整个复合材料的微裂纹,即软相尺寸从微米级减小到亚微米级时,增韧机制由软相对裂纹的阻挡转变为微裂纹的增殖和均匀分散。该研究结果为制备高强韧铝基复合材料提供重要参考价值。     

微致动技术

一、引言微致动指致动机构能够产生微米～纳米级的运动。应用于精微操作中的微致动机构,致动器本身并未微小化;而在微型机械领域,其致动器自身的尺寸也微小到了毫米乃至微米级的范围。微机械尺寸小、运动范围小、运动精度高且有一定的输出功率,所以作为其心脏的微致动需具有以下性能:1.微致动器尺寸微小;2.能产生大的力和线位移;3.更有效地应用三维形状以增大功率容量;4.更有     

聚合物球形微粒作为新型水基润滑添加剂的研究

根据边界润滑中的“滚珠”模型,将聚合物球形微粒（ＰＭＢ）作为新型的润滑添加剂引入到水基润滑中。扫描电镜测试表明ＰＭＢ在水基液中为均匀分散的微米级球形微粒。四球机测试结果显示ＰＭＢ加入选定的两种水基液中,水基液的极压抗磨性能都得到较大幅度的提高,ＰＭＢ在水基液中的含量有最佳浓度范围存在。结合ＰＭＢ的特殊结构特征,推测ＰＭＢ润滑机理中有微观的滚动和成膜。     

纳米级PMA润滑剂的合成及其抗磨性能

采用乳液聚合法合成了纳米级PMA润滑剂,用透射电镜（TEM）测定其粒径小100nm;将其分散到水中制得微乳液,用四球机考察其抗磨性能。实验结果表明,纳米PMA具有良好的抗磨性能,其抗磨机理可能是在低载荷下形成沉积膜,并起类似“滚珠轴承”的作用,在高载荷下形成聚合物保护膜,从而提高抗磨性。     

MEMS微电子机械系统与流程工业自动化

1 引言 在20世纪80年代,随着美国借助半导体集成电路制造技术研制成功微米级的硅微型静电电机而形成了微机械领域.     

微型磨料射流加工技术的现状及应用前景

产品小型化和加工过程微型化是目前世界制造加工行业的发展趋势，机械制造业的可靠加工水平仍在微米级或亚微米级。微型磨料射流直径为10－100μm，很容易在金属、陶瓷和聚合物等几乎所有材料上切割和钻孔，是一种具有广阔应用前景的新兴微型加工技术。     

掺苝聚合物微球的制备及研究

为了获得高Q值激光器,利用光学微球谐振腔具有高Q值、低阈值和利于集成化等优点,制备了掺苝聚合物微球。通过改变实验试剂的用量,实现了对微球直径的控制。研究表明：所制备的微球表面光滑,形貌特征完好,是优良的回音壁腔体;在飞秒激光泵浦下,无论是单个微球还是聚集的微球都能激发出激光,具有良好的应用前景。     

硅微半球陀螺频率裂解修调工艺规律仿真分析

频率裂解是影响半球谐振陀螺性能的主要因素之一.硅微半球陀螺谐振子球壳的厚度为μm量级,半径为mm量级,小而脆弱的谐振子导致修调难度大,针对此问题,文中通过有限元仿真的方法分析了在硅半球壳谐振子唇边进行打孔对频率裂解的影响规律.得到了"应该在低频模态上打孔以减小频率裂解"、"修调的加工精度需要在微米级甚至是亚微米级"、"...     

Novel sample preparation method of polymer emulsion for SEM observation

The aim of this study was to design a simple and reliable method for obtaining the detailed information about the average size, size distribution, and the surface morphology of particles with variation of the sample preparation of a polymer emulsion. In this work, the characteristic features of the particles of rosin size with high viscosity were first described by scanning electron microscopy (SEM). The morphologies of polymer emulsion of solid lipid nanoparticles and of the microspheres were observed. The advantage of the method is that not only the true size and shape of emulsion particles can be shown, but the problem of high-viscosity emulsion that prevents there study with SEM is solved. Using this new method, the micromorphology and size distribution of the emulsion particles with different viscosities have been clearly observed.     

Development and characterization of fast responding pressure sensitive microspheres

The response times of pressure sensitive paint (PSP) and pressure sensitive microspheres to passing shockwaves were measured to investigate their ability to accurately determine pressure changes in unsteady flows. The PSPs tested used platinum tetra(pentafluorophenyl)porphine (PtTFPP), platinum octaethylporphine (PtOEP), and a novel set of osmium-based organometallic complexes as pressure sensitive luminophors incorporated into polymer matrices of dimethylsiloxane bisphenol A-polycarbonate block copolymer or polystyrene. Two types of pressure sensitive microspheres were used, the first being PtOEP-doped polystyrene microspheres (PSBeads) and the second being porous silicon dioxide microspheres containing the novel, pressure sensitive osmium complexes. Response times for the platinum-based PSPs ranged from 47.2 to 53.0 micros, while the osmium-based PSPs ranged between 37.6 and 58.9 micros. For the microspheres, 2.5 microm diameter PSBeads showed a response time of 3.15 ms, while the osmium-based silicon dioxide microspheres showed a response time ranging between 13.6 and 18.9 micros.     

Evaluation of imperfections in silica and chalcogenide glass microspheres using focussed ion beam milling and imaging

Microspheres made from optical glasses such as silica and chalcogenide are used as both passive and active optical elements in micro-optics systems and devices. The homogeneity of the microspheres is crucial to their optical quality and performance in such devices and so it is essential, in optimizing such systems, that techniques with nanometer scale resolution are developed to measure the internal structure and homogeneity of such spheres. In this work an analytical protocol based on focussed ion beam milling, combined with secondary ion and secondary electron imaging, has been developed to study the internal homogeneity of glass microspheres. The results have shown that silica microspheres with diameters of three to five microns, fabricated by a sol-gel method, have internal inhomogeneities and voids that will lead to non-uniform optical properties. The FIB milling and imaging technique developed has been found to be a very useful method of studying such inhomogeneities, which have been proposed, but never previously observed, in glass microspheres. The FIB based technique has also been used on larger chalcogenide glass (Ga(2)S(3):La(2)S(3)) microspheres (diameter of order 70 microns) but no inhomogeneities have been observed at the spatial resolution of a few microns so far achieved for these larger microspheres. This study suggests that the FIB based milling and imaging technique may have potential for quantitative use in the measurement of morphological variations in such systems as well as in the study of aging processes in micron-sized glass spheres.     

脉冲磁场辅助磁性复合磨粒化学机械抛光技术及其加工试验研究

提出一种脉冲磁场辅助新型磁性复合磨粒化学机械抛光技术。该技术利用磁性聚合物微球与SiO2磨粒组成的复合磨粒抛光液,在脉冲磁场辅助作用下,实现磨粒尺寸对硬质抛光盘微观形貌依赖性小、磨粒易进入抛光区域、材料去除率较高的抛光。设计了“之”字形的对位式结构电磁铁,模拟计算表明其磁感应强度沿抛光平面分布均匀,磁性微球受到的磁力一致性好。磁性微球在抛光系统中的受力分析表明：磁性微球受磁力作用时有利于复合磨粒从近抛光区进入抛光区,以二体磨损的方式去除加工表面;磁性微球不受磁力作用时,复合磨粒随抛光液的流动而移动,避免大量聚集形成磁链。以表面粗糙度Ra=1.1μm的硬质抛光盘进行硅片抛光试验,施加不同频率和占空比的脉冲磁场前后,硅片的去除率从137nm/min提高到288nm/min,频率5Hz、占空比50%时获得最大值,硅片表面粗糙度由抛光前Ra=405nm减小到Ra=0.641nm。     

Observation particle morphology of colloidal system by conventional SEM with an improved specimen preparation technique

On the basis of our previous report that polymer emulsion with different viscosity can be investigated by conventional scanning electron microscopy (SEM), we have developed an improved specimen preparation technique for obtaining particle morphology and size of colloidal silver, collagen, glutin, and polymer microspheres. In this study, we expect to provide a means for charactering the three-dimensional surface microstructure of colloidal particles. Dilution of the samples with appropriate volatile solvent like ethanol is effective for SEM specimen preparation. At a proper ratio between sample and ethanol, the colloidal particles are dispersed uniformly in ethanol and then deposited evenly on the substrate. Different drying methods are studied to search a proper drying condition, in which the small molecule solvent is removed without destroying the natural particle morphology. And the effects of ethanol in the specimen preparation process are described by analyzing the physicochemical properties of ethanol. The specimen preparation technique is simple and can be achieved in common laboratory for charactering the particle morphology of colloidal system.     

Water-Based Lubrication of Hard Carbon Microspheres as Lubricating Additives

Because of their superior physical and chemical stability, carbon microspheres have been identified as promising lubricating additives. In this paper, hard carbon microspheres with diameters ranging from approximately 130 to 250 nm were prepared through a hydrothermal method using glucose as the carbon source. The as-prepared carbon microspheres were characterized by a series of complementary techniques including field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. It was found that the as-prepared carbon microspheres were spherical with graphitic structure. The effects of applied load, concentration, and particle size of the carbon microspheres as water-based lubricating additives against an opposing smooth silicon surface were systematically studied using a UMT tribometer and a 3D noncontact interferometric microscope. The results showed that carbon microspheres can effectively reduce friction and wear on a smooth silicon surface and the optimal performance was obtained at an applied load of 100 mN, a concentration of carbon microspheres of 0.1 wt% and an average particle size of 200 nm. The superior performance of carbon microspheres as water-based lubricating additives was attributed to having the particles dispersed as individual particles (as opposed to clusters) and also having sufficient physically and chemically stable particles within the contact region which allowed for a rolling friction mechanism to reduce friction.     

Novel impedance cell for low conductive liquids: determination of bulk and interface contributions

A plane capacitor cell with variable gap has been designed in order to detect the complex permittivity of low conductive liquids (up to 500 microS/cm) and the impedance of the sample-electrode interface. The novelty of the cell consists of the simultaneous presence of the field uniformity ensured by a guard ring, an adjustable gap between 300 microm and 6.75 mm (the electrode axial motion avoiding any rotation), and the immersion of the capacitor in the sample reservoir. The size of the capacitor electrodes and the gap values have been tested via the capacitance detection of the in-air cell at 1 kHz. The sample measurements have been performed by scanning the frequency range between 15 Hz and 2 MHz at four different capacitor gap values. In the paper a method to directly extract the bulk complex permittivity and the interface impedance versus frequency is presented. It is based on the assumption that the interface contribution is independent of the electrode gap, as confirmed (within the measurement accuracy) from measurements on all samples investigated. As samples of interest, we have chosen two certified electrolytic conductivity standards, KCl aqueous solutions having conductivity traceable to SI units; and two polymer latex aqueous dispersions of microspheres. Regarding KCl solutions, the conductivity measurements are compatible with the reference values within the specified uncertainty; the measured permittivities are consistent with the literature. For all samples, we have recovered the expected result that the interface impedance mainly affects the low frequency range (f<10 kHz).     

磁性复合磨粒化学机械抛光技术及其加工试验研究

提出一种新型的磁性复合磨粒化学机械抛光技术。该技术利用磁性聚合物微球与SiO2磨粒组成的复合磨粒抛光液,在辅助磁场的作用下,实现了一种磨粒尺寸与硬质抛光盘微观形貌依赖性小、材料去除率较高的抛光工艺。建立直径8 mm、高度不等的稀土钕铁硼永磁体以点阵形式组合形成的4类辅助磁场。仿真计算表明,柱状下凹磁极的磁场磁力HdH/dz分布均匀,磁性微球受到的磁力一致性好。对磁性微球在抛光系统中的受力分析表明,磁性微球受到的磁力有助于复合磨粒从近抛光区域进入抛光区域,磁性复合磨粒能以二体磨损的方式划擦去除加工表面。以表面粗糙度Ra 0.5μm的硬质抛光盘进行硅片抛光试验,施加辅助磁场前后,硅片的材料去除率从66 nm/min提高到179 nm/min,硅片表面粗糙度由抛光前Ra 405.860 nm减小到Ra 0.490 nm。     

A drag reduction in cwm transportation with polymer additives

Experimental investigations have been carried out to determine the drag reduction produced by polymer additives in coal water mixture (CWM) and hydraulic tranports. Different values of flow velocities, polymer concentrations and different temperatures were adopted to obtain a clear picture about the process involved. The additives are polyox WSR-301 and separan AP-273 in coal and deionized water mixtures. The experiments were undertaken with a test section pipe diameter 9.8mm and lenght 3500mm in a closed loop. The criteria used is to produce the amount of drag reduction and have the stability against degradation with reliable polymer additives. It is found that the drag reduction on CWM containing polymer is greater at higher flow velocities and in “pure” polymer solutions than CWM containing polymer. Furthermore, polymer concentrations at which drag reduction reached a maximum have been investigated.     

Three-dimensional dynamic morphometry on a diffraction pattern in the focal plane

A new type of morphometry, which shortens the scanning time of precise observation by confocal microscopy, has been investigated. To analyse the 3-D distribution of active sites on a living cell, microspheres of the same size were immunologically marked on specific sites on a cell. Incident coherent light was scattered on the microspheres and the scattered light from each microsphere superimposed upon each other giving a diffraction pattern of the examined cell. Several series of interference fringes were generated on the diffraction pattern, according to the phase difference of the microspheres. These interference fringes on the 2-D diffraction pattern enable the (relative) 3-D positions of the microspheres to be determined. 3-D dynamic morphometry on a 2-D diffraction pattern with interference fringes speeds up imaging in confocal microscopy.