Preparation of porous Fe2O3/SiO2 nanocomposite abrasives and their chemical mechanical polishing behaviors on hard disk substrates

Abrasives play an important role in chemical mechanical polishing (CMP) processes. Compact solid silica particles, which have been widely used as abrasive in CMP slurries, may cause surface defects because of their high hardness. Porous silica abrasive exhibits better surface planarization and fewer scratches than traditional solid silica abrasive during the polishing of hard disk substrates. However, the improvement in material removal rate (MRR) was not significant. Therefore, porous Fe₂O₃/SiO₂ nanocomposite abrasives were prepared and their CMP performances on hard disk substrates were investigated. Experiment results indicate that the MRR of slurry containing porous Fe₂O₃/SiO₂ nanocomposite abrasives is obviously higher than that of slurry containing pure porous silica abrasive under the same testing conditions. MRR increases with the increase of the molar content of iron in porous Fe₂O₃/SiO₂ nanocomposite abrasives. Moreover, surfaces polished by slurries containing the porous Fe₂O₃/SiO₂ nanocomposite abrasives exhibit lower surface roughness, fewer scratches as well as lower topographical variations than that by pure porous silica abrasive.     

Synthesis of Zn-doped colloidal SiO<Subscript>2</Subscript> abrasives and their applications in sapphire chemical mechanical polishing slurry

In this paper, Zn-doped colloidal SiO₂ composite abrasives were synthesized by seed-induced growth method and used to polish sapphire substrates. Time of flight secondary ion mass spectroscopy and scanning electron microscopy analyses show that element zinc has been doped into colloidal SiO₂, and the prepared Zn-doped colloidal SiO₂ composite abrasives are all ideal spherical and have good dispersibility. Chemical mechanical polishing (CMP) performances of Zn-doped colloidal SiO₂ composite abrasives on sapphire substrates were investigated using UNIPOL-1502 CMP equipment. Experimental results show that, under the same testing conditions, the surfaces of sapphire polished by Zn-doped colloidal SiO₂ composite abrasives exhibit lower root mean square roughness and higher material removal rate (MRR) than those of pure colloidal SiO₂ abrasive. Especially, the composite abrasive shows the maximum MRR at 1.0 wt% Zn(OH)₂ content. Furthermore, the acting mechanism of Zn-doped colloidal SiO₂ composite abrasives in sapphire CMP was analyzed by X-ray photoelectron spectroscopy, and analytical results show that element zinc in composite abrasives can react with sapphire substrate to form aluminum zincate (Al₂ZnO₄) during CMP, which promotes the chemical effect in CMP and leads to the improvement of MRR.     

静电自组装制备复合磨粒及其 对铜的抛光特性研究

研究苯代三聚氰胺甲醛（BGF）微球与阳离子型聚电解质聚二烯丙基二甲基氯化铵（PDADMAC）、阴离子型聚电解质聚4－苯乙烯璜酸钠（PSS）之间的吸附特性,利用静电自组装技术改变和控制BGF微球的荷电特性,制备出不同形式的PEi BGF/SiO2复合磨粒,以Zeta电位、透射电子显微镜（TEM）和热重分析（TG）等手段对复合磨粒进行了表征,并利用这些复合磨粒制备了铜片抛光用的复合磨粒抛光液。抛光试验表明,吸附在聚合物微球表面和游离于抛光液中的SiO2磨粒在抛光中均起到材料去除作用。传统单一SiO2磨粒抛光液的铜材料去除率为264 nm/min,PE0 BGF/SiO2混合磨粒抛光液的铜材料去除率为348 nm/min,PE3 BGF/SiO2复合磨粒抛光液的铜材料去除率为476 nm/min。经上述3种抛光液抛光后的铜表面,在5 μm×5 μm范围内,表面粗糙度Ra从0.166 μm分别降至3.7 nm、2.6 nm和1.5 nm,峰谷值Rpv分别小于20 nm、14 nm和10 nm,复合磨粒抛光液对铜片有良好的抛光性能。     

Enhancement of the light extraction efficiency in organic light emitting diodes utilizing a porous alumina film

The light extraction efficiencies of organic light emitting diodes (OLEDs) utilizing various kinds of porous alumina films with different pore diameters were investigated. The OLEDs with the porous alumina film deposited on the glass surface were fabricated to improve their light extraction efficiency. The porous alumina film was fabricated by using a two step anodizing electrochemical procedure. The current densities as functions of the applied voltage do not significantly change, regardless of the existence and the magnitude of the pore diameter in the porous alumina film. The luminance efficiency of the OLEDs increased with increasing pore diameter. The luminance efficiency of the OLEDs utilizing the porous alumina film with a pore diameter of 70 nm was enhanced approximately 9% in comparison with that of the OLEDs without the porous alumina film. These results indicate that highly efficient OLEDs can be fabricated using a porous alumina film with an optimum pore diameter.     

基于溶胶凝胶法的纳米磨料抛光工具基体特性研究(英文)

相对于传统化学机械抛光(CMP)技术存在的磨料浪费和抛光液污染环境等问题,一种以海藻酸钠(SA)水凝胶为基体的纳米磨料抛光工具开始展现其潜在的应用前景和环保优势.为了解决凝胶干燥成膜过程中基体严重收缩导致的磨料层很薄以及储存过程中基体继续失水引起的工具表面干裂失效等问题,采用了向基体中添加干燥控制化学添加剂(DCCA)的方法;并通过正交实验和极差分析,分析了不同DCCA对基体收缩的影响程度,选择了最佳的添加剂浓度配比.最后通过硅片抛光试验,对改良后的工具加工性能进行了检验.试验结果表明,向基体中添加质量分数为4%的纳米二氧化硅、12%的蔗糖和0.14%的十二烷基硫酸钠(SDS)对基体收缩的抑制效果最明显,磨料层的厚度提高了1.7倍,且在储存过程中不再出现明显的脱水失效.同时,该工具的基体变成了疏松多孔的结构,进而提高了工具的加工性能.     

准晶磨料对不锈钢亚表层强化形为的有限元仿真

新型准晶磨料与传统金刚石和Al₂O₃磨料进行对比研究,利用单颗粒模型,针对现实复杂工况情况,选取圆形、三角形、梯形和刀形四种典型磨粒形状,分别对不锈钢表面进行切削有限元仿真。结果表明:针对不同形状的磨粒,圆形磨粒对不锈钢纵向亚表层的影响最深。不锈钢表面经九次反复切削累积,圆形的等效应力是刀形的2.6倍,圆形的等效应变是三角形的5倍。磨粒反复切削工件表面后,针对不同磨料,准晶磨料对不锈钢亚表层的等效应力纵向影响深度大于金刚石和氧化铝。经准晶、金刚石和Al₂O₃磨料处理的表层最大的平均等效应变分别为77%、75%、45%。准晶磨料无论是圆形磨粒或尖角刀形磨粒,对不锈钢表面的作用机制都更倾向于塑变疲劳磨损。     

Effect of Polishing Conditions on the Optical Properties of Zinc Selenide Surfaces

The effects of the polish time and the pressure applied to the sample on the quality of polycrystalline ZnSe surfaces prepared by mechanical polishing with fine-particle abrasives on wheels made of pitch–colophony resins are studied. The results indicate that, using 1-m alumina as an abrasive and distilled water as an extender, the fourth surface finish class (RF Standard GOST 11141-84) with deviations from planarity less than half of an interference fringe at a sample diameter of up to 40 mm can be achieved at pressures applied to the sample from 30 to 35 kPa and polish times longer than 225 min. The material removal rate under the optimal polishing conditions is 0.03 m/min.     

基于游离磨粒的化学机械抛光材料去除非均匀性形成机制(英文)

本文主要研究硬脆晶体材料化学机械抛光中基片内材料去除非均匀性的形成机理.首先分析了化学机械抛光时抛光机的运动参数对硅片表面上相对速度分布非均匀性、摩擦力分布非均匀性、接触压力分布非均匀性及磨粒运动轨迹密度分布非均匀性的影响规律.然后通过基片内材料去除非均匀性实验,得出了抛光机运动参数对基片表面材料去除非均匀性的影响.通过比较理论分析与实验结果,基片表面上相对速度分布非均匀性、摩擦力分布非均匀性及接触压力分布非均匀性随转速的变化趋势与基片表面材料去除非均匀性的实验结果相差较大,只有磨粒在基片表面上的运动轨迹分布非均匀性与基片表面材料去除非均匀性的实验结果趋势相同.研究结果表明,基片表面材料去除非均匀性是由磨粒在基片表面上的运动轨迹分布非均匀性造成的,充分说明了基片表面材料去除的机械作用主要是磨粒的机械作用.     

Chemical mechanical polishing of hard disk substrate with α-alumina-g-polystyrene sulfonic acid composite abrasive

α-Alumina-g-polystyrene sulfonic acid (α-Al₂O₃-g-PSS) composite abrasive was prepared by surface activation, graft polymerization and sulfonation, successively. The composition, dispersibility and morphology of the product were characterized by Fourier transformed infrared spectroscopy, laser particle size analysis and scanning electron microscopy, respectively. The chemical mechanical polishing (CMP) performances of the composite abrasive on hard disk substrate with nickel-phosphorous plating were investigated. The microscopy images of the polished surfaces show that α-Al₂O₃-g-PSS composite abrasive results in improved CMP and post-CMP cleaning performances than pure α-alumina abrasive under the same testing conditions.     

Metallographic preparation of soft materials: Lead alloys

Metallographic preparation of lead and its alloys is notoriously difficult due to the low hardness of the material and its tendency to pick up and embed abrasive particles readily. Working with component parts for lead acid batteries at Lucas Advanced Vehicle Systems Development, the odd shapes and sizes, such as connector posts and intercell welds, do not lend themselves to microtoming or electropolishing. Vibratory polishing had been used in the past but this method could take up to 6 days to produce an acceptable microsection. Using semiautomatic polishing equipment had proved more successful, but again long periods of time were taken to produce satisfatory results with all the problems of lubricant and abrasive dosing. Tests on newer, commercially available pads and abrasives provided by various manufacturers have been carried out, but it was found that a combination of machining, polishing with diamond, and final polishing with alumina gave the best results. The use of automatic polishing equipment made the preparation easier with both contrarotation and complementary rotation directions. Lubricants and abrasives recommended by the metallographic consumable suppliers for soft materials were not suitable for the easily stained and oxidized lead alloys. This report lays out the steps taken to produce the stated optimized procedure and shows some unusual structures that have been revealed in components taken from batteries undergoing testing, one of which had suffered explosive damage.     

Effect of abrasives on the glossiness and reflectance of anodized aluminum alloys

Blasting can eliminate or change the surface texture of as-rolled aluminum alloy by indentation to roughen the alloy’s surface. We investigated the effects of the blasting conditions on the glossiness and reflectance of Al1050-H16 and Al5052-H32 alloys in this study. As-rolled sheets were blasted at various pressures, and then removed for sequential cleaning, chemical polishing, and anodizing steps. After each step the samples were measured by micro-TRI-gloss meter and spectrophotometer to compare the effects produced by the abrasive powders and processing variables. Polyhedral alumina and round iron powders were used as the blasting media. The glossiness (Gs(60°)) decreased as the root mean square roughness (Rq) increased, regardless of the shape of the abrasive powders. The abrasives powders could cause wear and/or fracturing during the blasting process as well as fine debris, which could become embedded in the blasted surface. When an aluminum alloy was blasted with iron powders, the glossiness value after alkaline etching and chemical polishing was greater than that after being blasted with alumina; while the anodized Al5052-H32 alloy’s surface became more yellowish in color.     

Fine Machining of Large-Diameter 6H-SiC Wafers

Three main machining processes of large-diameter 6H-SiC wafers were introduced in this paper. These processes include cutting, lapping and polishing. Lapping causes great residual stresses and deep damage layer which can be reduced gradually with subsequent polishing processes. Surfaces prepared by mechanical polishing （MP） appeared a large number of scratches with depth of 5-8 nm. These scratches can be effectively removed by chemo-mechanical polishing （CMP）. After CMP. extremely smooth and low damage layer surface with roughness Ra=0.3 nm was obtained. Atomic force microscopy （AFM） and optical microscopy were used to observe the surface morphology of samples and a high resolution X-ray diffractometer （HRXRD） was used for the crystal lattice perfection of the subsurface region. Changes of surface residual stresses during machining processes were investigated by HRXRD.     

Preparation and magnetic properties of cylindrical NiFe films and antidot arrays

Continuous NiFe (Permalloy) cylindrical films and arrays of cylindrical NiFe antidots 7 nm thick have been prepared by sputtering onto cylindrical aluminum wires and onto wires anodized to form a porous anodic alumina layer. The antidots are arranged in a close-packed pattern determined by the hexagonal pore arrangement in the porous alumina, with period 103 nm and diameter 42 nm. Hysteresis loops were measured at different angles with respect to the cylinder axis and indicate an easy plane normal to the radius of the wire. The antidots enhance the coercivity compared to the continuous cylindrical film.     

树枝状介孔氧化硅磨粒的制备和抛光性能

使用油水双相分层反应体系(以萘烷为上层油相)制备了具有Y型孔道的树枝状介孔氧化硅颗粒(DMSPs)。透射电镜、扫描电镜、X射线衍射、氮气吸附/脱附和粒度分布的测试结果表明:所得DMSPs样品的粒径为72±6 nm,在液相环境中粒度的分布较窄;其内部的三维中心辐射状介孔孔径为6~8 nm,但是孔道结构没有长程有序性。氧化硅片经DMSPs磨粒抛光后表面的粗糙度均方根值由0.76下降至0.21 nm,最大轮廓波峰高度由1.48下降至0.50 nm、最大波谷深度则由1.86下降至0.45 nm,材料去除率高达187 nm/min。讨论了DMSPs磨粒在界面摩擦磨损和接触粘附过程中的作用机制。     

以修饰的PAA模板制备Ni纳米线的研究

采用直流电沉积法制备了Ni纳米线,用SEM和TEM测试手段观察产物形貌,结果表明,合成的纳米线阵列具有排列有序、彼此平行等特点,XRD、EDX、SQUID测试手段研究了产物化学成份和磁学性质,实验发现,Ni纳米线的矫顽力在退火前后分别为67 Oe和774 Oe。     

Effect of the Cd<Subscript>0.96</Subscript>Zn<Subscript>0.04</Subscript>Te substrate polishing procedure on Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Hg<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Te liquid phase epitaxy

This paper examines the effect of polishing procedure on the surface quality of Cd_0.96Zn_0.04Te substrates for Cd _x Hg_{1 − x} Te liquid phase epitaxy. Two polishing procedures are tested: stepwise polishing involving abrasive, chemomechanical, and chemical steps with the use of various abrasives, and abrasive-free polishing. The optimal procedure is chemomechanical polishing with no abrasives. The type of substrate surface can be identified using the Nakagawa etchant, which produces etch patterns in the form of triangles on the A(111) surface and circles on the B(111) surface.     

Optimization of Polishing Parameters with Taguchi Method for LBO Crystal in CMP

Chemical mechanical polishing(CMP)was used to polish Lithium triborate(LiB3O5 or LBO)crystal.Taguchi method was applied for optimization of the polishing parameters.Material removal rate(MRR)and surface roughness are considered as criteria for the optimization.The polishing pressure,the abrasive concentration and the table velocity are important parameters which influence MRR and surface roughness in CMP of LBO crystal.Experiment results indicate that for MRR the polishing pressure is the most significant p...     

电化学阳极氧化法制备有序多孔材料的研究进展

阳极氧化法制备有序多孔材料具有工艺简单、孔径可控以及稳定性高等特点,具有广阔的应用前景.系统介绍了阳极氧化法制备有序多孔氧化铝和氧化钛的研究进展.重点介绍了阳极氧化法制备小孔径有序多孔氧化铝和氧化铝光子晶体的研究,特别介绍了有序多孔氧化钛膜的结构特点及该领域未来的发展方向.此外还简略介绍了阳极氧化法制备ZrO2、HfO2等有序多孔材料.     

精细雾化抛光氮化硅陶瓷的抛光液配制参数优化

采用超声精细雾化施液抛光对氮化硅陶瓷基体进行抛光,研究了不同的pH值、磨料浓度以及氧化剂含量对氮化硅陶瓷基体抛光的材料去除率的影响,优化了pH值、磨料浓度及氧化剂含量,并与传统的化学机械抛光进行了对比。结果表明:当二氧化硅磨粒质量分数为5wt%,氧化剂含量为1wt%,pH值为8时,材料去除率MRR为108.24nm/min且表面粗糙度Ra为3.39nm。在相同的抛光参数下,传统化学机械抛光的材料去除率MRR为125nm/min,表面粗糙度Ra为2.13nm;精细雾化抛光的材料去除率及表面粗糙度与传统抛光接近,但精细雾化抛光所用抛光液用量仅为传统抛光所用抛光液用量的1/9。     

CVD金刚石膜高效超精密抛光技术

CVD金刚石膜作为光学透射窗口和新一代计算机芯片的材料,其表面必须得到高质量抛光,但是现存方法难以满足既高效又超精密的加工要求.本文提出机械抛光与化学机械抛光相结合的方法.首先,采用固结金刚石磨料抛光盘和游离金刚石磨料两种机械抛光方法对CVD金刚石膜进行粗加工,然后采用化学机械抛光的方法对CVD金刚石膜进行精加工.结果表明,采用游离磨料抛光时材料去除率远比固结磨料高,表面粗糙度最低达到42.2 nm.化学机械抛光方法在CVD金刚石膜的超精密抛光中表现出较大的优势,CVD金刚石膜的表面粗糙度为4.551 nm.