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...     

Magnetorheological nanofinishing of BK7 glass for lens manufacturing

BK7 is a high-quality crown glass which is used where additional benefits such as temperature sensitive applications of fused silica glass are not required. Due to very low inclusion content with extremely low bubbles, BK7 glass can find its application in lens manufacturing. The present work focuses on nanofinishing of the BK7 glass specimen for ratifying its utility in practical application. A programmable logic controlled 3-axis motions are fed to the magnetorheological (MR) rotating tool for finishing the glass specimen. MR polishing fluid used for nanofinishing consists of deionized water, magnetic iron particles, and cerium oxide powder. Under the influence of magnetic field, the stiffened MR polishing fluid is assisted in reducing the surface roughness of glass up to nanolevel range. Optical properties such as transmittance, absorbance, and reflectance of finished BK7 glass are analyzed and found suitable for lens manufacturing. Results of higher surface quality with excellent finishing are obtained by the present MR finishing process. After 90?min of finishing, the surface roughness values R_a and R_q are reduced to 17 and 27?nm from the initial values of 41 and 57?nm, respectively. To study the surface morphology, scanning electron microscopy is performed on BK7 glass.     

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.     

化学机械抛光技术及SiO2抛光浆料研究进展

随着半导体工业和集成电路(IC)工艺的飞速发展,化学机械抛光(CMP)作为目前唯一能提供超大规模集成电路(VLSI)制造过程中全面平坦化的一种新技术,已成为各国争相研究的热点。介绍了CMP技术的产生、优势、发展、理论、设备与耗材;着重介绍了SiO2浆料的国内外研究现状,并展望了CMP技术及SiO2浆料的研究开发和应用前景。     

SiC单晶片的超精密加工

半导体晶片的加工质量和精度,直接影响到器件的性能.本文提出了一种超精密加工SiC晶片的方法,并详细论述了化学机械抛光的原理.加工后的SiC单晶片,平整度为±3μm,粗糙度＜5nm,且应力较小.     

Ni-Ti形状记忆合金电化学抛光工艺研究

为提高Ni-Ti形状记忆合金的表面质量,以Ti50.8Ni(原子分数,%)为基材进行纳米级电化学抛光加工试验。基于自行研制的电化学抛光加工系统及抛光液,通过正交试验和单因素试验,分析了电流密度、抛光时间、抛光温度、电极间距等因素对电化学抛光的影响程度及影响机理。采用Micro XAM-100白光干涉仪对抛光试样进行检测。结果表明:最佳抛光工艺为电流密度J=1.0 A/cm2、电极间距d=15 mm、抛光时间t=140 s、抛光温度θ=15℃。在最佳工艺参数下抛光质量良好,试件表面粗糙度值显著降低至27.8 nm,表面平整均匀、光亮如镜。     

Bound-abrasive polishing of precision surfaces of nonmetallic materials

A mechanism of the microrelief generation on a surface being polished is described based on the cluster model and the physical-statistical model of the workpiece material debris formation. It is demonstrated that the removal rate in polishing nonmetallic materials decreases exponentially with increasing bond energy in these materials and the polished surface roughness depends on the ratio of natural frequencies of molecular fragments on the tool and workpiece surfaces.     

Surface roughness in diamond abrasive finishing

Polished surface roughness is shown to depend on a ratio of natural vibration frequencies of molecular fragments on the tool and workpiece surface. The factors that have the greatest effect on the machined surface roughness are the following: (a) the number of molecular fragments the debris particles consist of, (b) the most probable size of the particles, (c) natural vibration frequencies of the fragments of the tool and workpiece materials, (d) workpiece material thermal conductivity, and (e) machining conditions.     

Surface polishing of 6H-SiC substrates

The surface polishing for silicon carbide （SIC） substrates was investigated and results were presented for mechanical polishing （MP） and chemo-mechanical polishing （CMP）. High quality surfaces were obtained after CMP with colloidal silica. The removal mechanism of scratches in MP and detailed physical and chemical process during CMP were analyzed. The effects of MP and CMP on the surface roughness were assessed by optical microscopy （OM）, atomic force microscopy （AFM） and step profilometry. KOH etching and high resolution X-ray diffractometry （H RXRD） were applied to evaluate the subsurface damage of 6H-SiC substrates.     

A theory of pad conditioning for chemical-mechanical polishing

Statistical models are presented to describe the evolution of the surface roughness of polishing pads during the pad-conditioning process in chemical-mechanical polishing. The models describe the evolution of the surface-height probability-density function of solid pads during fixed height or fixed cut-rate conditioning. An integral equation is derived for the effect of conditioning on a foamed pad in terms of a model for a solid pad. The models that combine wear and conditioning are then discussed for both solid and foamed pads. Models include the dependence of the surface roughness on the shape and density of the cutting tips used in the conditioner and on other operating parameters. Good agreement is found between the model, Monte Carlo simulations and with experimental data.     

精密U薄膜的制备及表征

采用机械磨抛、表面轮廓仪以及AES分析等方法，制备并表征了精密U薄膜。结果表明，获得了厚度从约50μm深减薄到约10μm厚的U薄膜，该薄膜的表面粗糙度Ra、Rq均低于50nm，但峰谷极差Tir大于100nm。薄膜越薄，Ra，Rq，Tir和厚度不一致性均有所增大，且薄膜的厚度一致性随着取样长度的增加有所减小。对实验结果进行了讨论。     

一种新的气囊式抛光方法的研究

针对气囊式小磨头抛光方法的缺陷,提出了一种新的气囊式抛光方法。本文对该气囊式抛光法的原理和抛光气囊的结构、运动方式等进行了阐述。在此基础上,结合装置开展了实验,给出了去除量、压力、粗糙度与时间的关系。研究结果表明,利用该气囊式抛光方法对非球面光学零件进行抛光,效果良好,表面粗糙度可达2nm,该方法能满足中高等精度的加工要求;该方法适合平面、球面、非球面、甚至任意曲面的抛光。     

Thermophysical Parameters of Optical Glass BK 7 Measured by the Pulse Transient Method

This paper is focused on the pulse transient method. The theory of the method and the measuring regime (time window) are analyzed. The results of the analysis are verified on borosilicate crown glass BK7, which is a candidate for a standard for thermal conductivity. Thermal contact and surface effects affect the length of the time window in which the evaluation procedure is applied. The one-point evaluation technique is compared with the results of the fitting procedure that uses the time window found by difference analysis. The values of the thermal conductivity, thermal diffusivity, and specific heat were found to be 1.05 W· m^–1 · K^–1, 0.548 × 10^–6m ^{– 2} · s^–1, and 767 J· kg^–1 · K^–1, respectively, using the one-point evaluation technique.Paper presented at the Sixteenth European Conference on Thermophysical Properties, September 1–4, 2002, London, United Kingdom.     

聚合物光波导端面磁流变抛光工艺(英文)

光波导端面的表面质量会严重影响光波导器件的光耦合封装性能,耦合封装前必须对波导器件端面进行抛光处理.目前聚合物光波导端面主要依靠传统研磨盘进行抛光处理,该工艺工序复杂、抛光效率低已成为制约聚合物波导器件应用的瓶颈.基于聚合物光波导材料优良的加工特性,通过对比实验提出了聚合物光波导的磁流变端面抛光工艺.采用5μm、0.5μm和1μm粒径的氧化铈抛光粉分别配制研磨盘抛光液及磁流变抛光液对3 mm×3 mm聚合物光波导端面进行抛光实验,发现磁流变加工对聚合物光波导端面进行一次2 m in光栅扫描抛光就具有比传统研磨盘约3 h精、粗抛光较好的端面质量.经过白光干涉仪测量,磁流变抛光后光波导端面表面粗糙度的均方根值达到了2.6 nm,传统端面抛光端面粗糙度均方根值为128.7 nm.通过自动对准耦合平台测试,结果显示通过磁流变端面抛光的光波导的插入损耗由抛光前的32.7 dB降低到了17.8 dB.磁流变抛光方法可以对聚合物光波导端面进行快速、高性能的抛光,在光波导应用领域具有非常广阔的应用前景.     

用碱性纳米SiO2浆料对计算机硬盘NiP基板进行CMP超精密加工的研究

采用碱性纳米SiO2浆料对计算机硬盘NiP基板进行CMP超精密加工,与酸性浆料对比,在平整度PV、均匀度rms和粗糙度RA均获得显著提高。     

复合抛光对 CVD金刚石薄膜表面光洁度的改进研究

采用激光抛光和热化学抛光相结合的方法，对通过热丝CVD方法生长的金刚石薄膜进行了复合抛光处理．并利用X射线衍射仪（XRD）、拉曼光谱仪（Raman）、扫描电子显微镜（SEM）和原子力显微镜（AFM）对金刚石薄膜进行了表征．结果表明，所合成的金刚石薄膜是高质量的多晶（111）取向膜；经复合抛光后，金刚石薄膜的结构没有因抛光而发生改变，金刚石薄膜的表面粗糙度明显降低，光洁度大幅度提高，表面粗糙度Ra在100nm左右，基本可以达到应用的要求．     

碲锌镉晶片机械研磨和机械抛光工艺研究

研究了碲锌镉(CZT)晶片表面的机械研磨和机械抛光工艺.采用不同粒度的Al2O3磨料对CZT晶体表面进行机械研磨和机械抛光,并研究了工艺参数变化对CZT晶体表面质量、粗糙度、研磨速度和抛光速度的影响.结果表明,机械研磨采用粒度2.5μm的Al2O3磨料,最佳的研磨压力和研磨盘转速分别为120g/cm.和75r/min,...     

A study of surface condition of sapphire (α-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>) workpieces upon their finishing operation

An experimental investigation of surface condition parameters (surface roughness Rmax and depth of affected surface layer F) of sapphire workpieces upon their finishing operations is carried out using advanced measurement instrumentation; some results are provided. The factors have been found which have an effect on the above-mentioned parameters and relation between them in the course of machining; this makes it possible to calculate machining allowances for each operation and design the machining process such that the highest requirements to optical surfaces will be met.     

Preparation of porous alumina abrasives and their chemical mechanical polishing behavior

Porous alumina abrasives with different pore sizes were prepared using hydrothermal synthesis method by different hydrothermal temperatures. The pore structure, pore size and pore volume of the products were characterized by transmission electron microscopy and nitrogen adsorption desorption isotherm measurement. The chemical mechanical polishing (CMP) performances of porous alumina abrasives in hard disk substrate CMP were investigated. The results show that, the polished surface average roughness (Ra) decreases when the pore diameter of porous alumina abrasive increases. By comparison with solid alumina abrasive, the prepared porous alumina abrasives give lower Ra, and the porous alumina abrasive with 8.61 nm pore diameter has higher material removal rate under the same polishing conditions.     

抛光液组分对硬盘盘基片超光滑表面抛光的影响

在硬盘盘基片的最终抛光中,研究SiO2溶胶颗粒、氧化剂、络合剂和润滑剂对盘基片Ni—P材料抛光性能的变化规律,获得较高的材料去除速率（MRR）和原子级光滑表面,以满足下一代硬盘盘基片制造的更高要求．结果表明,采用平均粒径25nm的SiO2溶胶颗粒,易减少微划痕等缺陷;以过氧化氢为氧化剂,可大幅提高MRR;加入有机酸络合剂后,MRR显著增大,其中含有水杨酸的抛光液MRR最大,并讨论不同络舍剂对盘基片去除的影响机理;丙三醇润滑剂的引入,使抛光中摩擦系数减小,盘基片的表面粗糙度得到明显降低．采用原子力显微镜（AFM）、光学显微镜和ChapmanMP2000＋表面形貌仪来考察盘基片抛光后的表面质量,基于抛光液各组分的影响作用,最终获得表面粗糙度尺。为0．08nm的盘基片表面,且MRR达到0．132μm／min．