pH值调节剂对Si片CMP速率的影响

通过一系列实验研究了有机和无机pH值调节剂对Si片抛光速率的影响及其影响机理。使用有机碱调节抛光液的pH值,随着pH值的增大,Si片的CMP速率先增大后减小,pH值为10.85时,Si片的抛光速率最大,为280nm/min;使用无机碱KOH代替有机碱调节抛光液的pH值时,抛光速率随pH值的增加而增大。无论使用何种pH值调节剂,pH值为10～11.5时,纳米SiO2溶胶的粒径能够稳定在43nm左右。随着pH值的升高,Si片与抛光液的反应越来越强烈,其反应产物在抛光液中的溶解度也会越来越大。pH值调节剂影响Si片表面钝化膜的形成速率和去除速率,并最终影响Si片化学机械抛光的效果。     

用于硬盘NiP基片CMP的一种碱性SiO_2抛光液

在NiP基片的化学机械抛光中,针对现有酸性抛光液存在的易腐蚀、易污染和以Al2O3为磨料造成易划伤表面的质量问题,尝试使用SiO2水溶胶作为抛光磨料,通过加入非离子表面活性剂和螯合剂等,配制成一种碱性环境下的硬盘基片抛光液。通过化学机械抛光试验,发现这种碱性SiO2抛光液在硬盘NiP基片抛光中具有250nm/min的抛光速率,抛光后的表面粗糙度为0.8nm,表面光滑,几乎观察不到划痕及其他微观缺陷。     

碱性抛光液对硬盘基板抛光中表面状况的影响

阐述了化学机械抛光(CMP)技术在硬盘基板加工中发挥的重要作用,介绍了SiO2碱性抛光液的化学机械抛光机理以及抛光液在化学机械抛光中发挥的重要作用。使用河北工业大学研制的SiO2碱性抛光液对硬盘基板表面抛光,分析研究了抛光液中的浓度、表面活性剂以及去除量对抛光后硬盘基板表面状况的影响机理。总结了硬盘基板表面粗糙度随抛光液中的浓度、表面活性剂及去除量的变化规律以及抛光液的这些参数如何影响到硬盘基板的表面状况。在总结和分析这些规律的基础上,对抛光结果进行了检测。经检测得出,改善抛光后的硬盘基板表面质量(Ra=0.3926nm,Rrms=0.4953nm)取得了显著效果。     

镁合金抛光机理与CMP工艺研究

将化学机械抛光(CMP)技术引入到镁合金片(MB2)的抛光中,打破过去镁合金以单一化学或机械加工为主的加工手段,用自制的抛光液对镁合金片进行抛光实验。结果发现,抛光液中加入双氧水易产生胶体,不利于抛光的进行,因此提出无氧化剂SiO2碱性抛光。同时分析了镁合金的抛光机理,抛光中压力、转速和抛光液流量参数对抛光过程的影响,利用Olympus显微镜对抛光前后镁合金表面进行观察,通过合理控制工艺参数,能够得到较佳的镁合金抛光表面,远优于单一的机械加工,为镁合金抛光工艺和进一步研究抛光液的配比奠定了基础。     

镁合金抛光机理与CMP工艺研究

将化学机械抛光（CMP）技术引入到镁合金片（MB2）的抛光中，打破过去镁合金以单一化学或机械加工为主的加工手段，用自制的抛光液对镁合金片进行抛光实验。结果发现，抛光液中加入双氧水易产生胶体，不利于抛光的进行，因此提出无氧化剂SiO2碱性抛光。同时分析了镁合金的抛光机理，抛光中压力、转速和抛光液流量参数对抛光过程的影响，利用Olympus显微镜对抛光前后镁合金表面进行观察，通过合理控制工艺参数，能够得到较佳的镁合金抛光表面，远优于单一的机械加工，为镁合金抛光工艺和进一步研究抛光液的配比奠定了基础。     

抛光液各组分在SiO_2介质CMP中的作用机理分析

介绍了超大规模集成电路中SiO2介质的化学机械抛光机理及抛光液在化学机械抛光中扮演的重要角色。通过单因素实验法,在低压力的实验环境下,着重分析了抛光液中表面活性剂、pH值调节剂、纳米磨料等成分在SiO2介质化学机械抛光中的具体作用及影响机理。最终得出,最优化的实验配比,即当表面活性剂的浓度为30mol/L,pH值为11.30,硅溶胶与去离子水的体积比为2:1时,在保证较低表面粗糙度的同时得到了较高的抛光速率476nm/min。     

基于白刚玉微粉的6H-SiC单晶基片化学机械抛光材料去除率研究

碳化硅单晶基片已广泛应用于微电子、光电子等领域,如集成电路、半导体照明(LED)等,本文根据前期的研究结果,以白刚玉微粉为磨料,通过大量的实验,研究了抛光液成分(PH值、磨粒粒径与含量、分散剂、氧化剂、活性剂)、抛光盘转速以及载物台转速对SiC单晶片(0001)Si面和C面化学机械抛光(CMP)时对材料去除率的影响。研究结果表明,在SiC晶体基片化学机械抛光时,抛光液在一定的pH值、一定的氧化剂含量、一定的分散剂含量、一定的磨粒含量及尺寸下,能够获得最佳的材料去除率;抛光盘的转速对材料去除率影响较大,材料去除率随抛光压力的增加而增大,C面的材料去除率远大于Si面的材料去除率,但无论是Si面或C面,抛光后表面无划痕,经过2个半小时的抛光,表面粗糙度达到Ra1nm以下。结果表明,氧化铝(Al2O3)磨粒可用于碳化硅单晶基片的化学机械抛光,其研究结果可为进一步研究SiC单晶片的高效低成本化学机械抛光液、抛光工艺参数及化学机械抛光机理提供参考依据。     

ULSI铜互连线CMP抛光液的研制

介绍了一种碱性抛光液,选用有机碱做介质,SiO2水溶胶做磨料,依据强络合的反应机理,克服了SiO2水溶胶做磨料对铜去除速率低及在溶液中凝胶的难点.实验结果表明:该抛光液适用于Cu化学机械抛光过程第一阶段的抛光,并达到了高抛光速率及铜/钽/介质层间的高选择性的效果.     

4H-SiC(0001)硅面原子级平整抛光方法

以4H-SiC(0001)面Si面为加工对象,提出了一种可以快速获得平整、无损伤表面的化学机械抛光方法。先在复合铜、锡盘上对2英寸(1英寸=2.54 cm)的SiC晶片进行机械抛光,去除研磨造成的损伤层和划痕,最后用特殊的抛光液进行化学机械抛光。用微分干涉显微镜和原子力显微镜观察晶片表面形貌的变化,观察结果显示,经3 h抛光后晶片的表面粗糙度状况得到了明显的改善,表面没有观察到划痕,表面粗糙度值达到了0.1 nm以下,并且出现规则排列的原子台阶构型,达到了原子级平整。实验研究了抛光液组成对抛光效果的影响,在最优的条件下,化学机械抛光的去除速率约为387 nm/h。     

ULSI铜互连线CMP抛光液的研制

介绍了一种碱性抛光液,选用有机碱做介质,SiO2水溶胶做磨料,依据强络合的反应机理,克服了SiO2水溶胶做磨料对铜去除速率低及在溶液中凝胶的难点.实验结果表明:该抛光液适用于Cu化学机械抛光过程第一阶段的抛光,并达到了高抛光速率及铜/钽/介质层间的高选择性的效果.     

Investigation on the controllable growth of monodisperse silica colloid abrasives for the chemical mechanical polishing application

With the rapid development of chemical mechanical polishing technique as well as its increasing application in IC foundry, the abrasives of slurry are required to have different specifications in terms of size and size’s distribution, which play a vital role in the material removal and defect control. In this study, we monitor in detail the growth process of colloidal silica abrasives changing from the tiny nuclei to large nanoparticles by means of the electron microscopy images. Using the procedure we develop, we are capable of producing monodisperse colloidal silica nanoparticles ranging from 60 to 130 nm in diameter, which are mostly often applied as abrasives in chemical mechanical planarization/polishing (CMP) process of integrated circuit (IC) manufacturing. The physicochemical properties of the silica synthesized by our procedure are also characterized by the X-ray diffraction (XRD) patterns and thermal analysis. The polishing test adopting the colloidal silica as abrasives is performed on silicon wafer to evaluate the CMP properties.     

A study on the chemical mechanical polishing of oxide film using a zirconia (ZrO2)-mixed abrasive slurry (MAS)

We have studied the chemical mechanical polishing (CMP) characteristics of mixed abrasive slurry (MAS) retreated by adding of zirconium oxide (ZrO₂) abrasives within 1:10 diluted silica slurry. These mixed abrasives in the MAS are evaluated with respect to their particle size distribution, surface morphology, and CMP performance such as removal rate and non-uniformity. As an experimental result, the comparable slurry characteristics when compared to the original silica slurry were obtained from the viewpoint of high removal rate and low non-uniformity for excellent CMP performance. Therefore, our proposed ZrO₂-MAS can be useful to save on the high cost of slurry consumption since we used a 1:10 diluted silica slurry.     

Material removal rate in chemical-mechanical polishing of wafers based on particle trajectories

Distribution forms of abrasives in the chemical mechanical polishing (CMP) process are analyzed based on experimental results.Then the relationships between the wafer,the abrasive and the polishing pad are analyzed based on kinematics and contact mechanics.According to the track length of abrasives on the wafer surface,the relationships between the material removal rate and the polishing velocity are obtained.The analysis results are in accord with the experimental results.The conclusion provides a theoretical guide for further understanding the material removal mechanism of wafers in CMP.     

基于磨粒运动轨迹的硅片化学机械抛光材料去率研究

硅片化学机械抛光（CMP）是机械作用与化学作用相结合的技术,硅片表面的化学反应层主要是由抛光液中磨料的机械作用去除,磨粒对硅片表面的摩擦和划擦对硅片表面材料的去除起着重要作用。磨粒在硅片表面上的划痕长度直接影响硅片表面的材料去除率。本文首先在实验结果的基础上分析了硅片CMP过程中磨粒的分布形式,然后根据运动学和接触力学理论,分析了硅片、磨粒及抛光垫三者之间的运动关系,根据磨粒在硅片表面上的运动轨迹长度,得出了材料去除率与抛光速度之间的关系,该分析结果与实验结果一致,研究结果可为进一步理解硅片CMP的材料去除机理提供理论指导。     

Inverse analysis of material removal data using a multiscale CMP model

This paper describes a mechanical model for a representative dual axis rotational chemical mechanical planarization (CMP) tool. The model is three-dimensional, multiscale and includes sub-models for bulk pad deformation, asperity deformation, lubrication based slurry flow, carrier film deformation, wafer compliance and material removal by abrasive particles in the slurry. With the model, material removal rate (MRR) can be determined as a function of stress applied to the wafer, relative sliding speed, and material and geometric parameters of the pad and slurry. Experimental material removal rate profiles obtained from Cu polishing experiments performed on a wafer without rotation are analyzed as an inverse problem. We use MRR data to predict local CMP conditions such as fluid film thickness, fluid pressure and contact pressure. The results are consistent with available experimental and analytical information. This inverse technique offers promise as an improved method of CMP model verification.     

ULSI制造中硅片化学机械抛光的运动机理

从运动学角度出发，根据硅片与抛光垫的运动关系，通过分析磨粒在硅片表面的运动轨迹，揭示了抛光垫和硅片的转速和转向以及抛光头摆动参数对硅片表面材料去除率和非均匀性的影响．分析结果表明：硅片与抛光垫转速相等转向相同时可获得最佳的材料去除非均匀性及材料去除率．研究结果为设计CMP机床，选择CMP的运动参数和进一步理解CMP的材料去除机理提供了理论依据．     

抛光工艺对硅片表面Haze值的影响

随着超大规模集成电路的快速发展,硅片表面的Haze值对于现代半导体器件工艺的影响也越来越受到人们的重视.通过实验研究了精抛光工艺参数对硅片表面Haze值的影响规律.结果表明,随着抛光时间的延长,硅的去除量逐渐增大,硅片表面Haze值逐渐降低;同时抛光过程中机械作用与化学作用的协同作用对Haze值也有较大影响.随着抛光液温度的降低与抛光液体积流量的减小,化学作用减弱,硅片表面Haze值逐渐减小.而随着抛光压力的增大,机械作用逐渐起主导作用,硅片表面Haze值逐渐降低.但当Haze值降低到某一数值后,随着硅去除量的增大、抛光液温度的下降、抛光液体积流量的降低、抛光压力的增大,硅片表面的Haze值基本保持不变.     

硅片CMP抛光工艺技术研究

介绍了硅片机械-化学抛光技术,重点分析了10.16 cm硅片抛光加工过程中抛光液的pH值、抛光压力和抛光垫等因素对硅片抛光去除速率及表面质量的影响.通过试验确定了硅片抛光过程中合适的工艺参数,同时对抛光过程中出现的各种缺陷进行了分析总结,并提出了相应的解决方案.     

Effects of process parameter variations on the removal rate in chemical mechanical polishing of 4H-SiC

The effects of temperature, slurry pH, applied pressure, and polishing rotation rate on the material removal rate during chemical mechanical polishing (CMP) of 4H-silicon carbide wafers using colloidal silica slurry and polyurethane/polyester fiber polishing pads have been studied. Measured removal rates varied from around 100 Å/hr to nearly 2500 Å/hr depending on the values of the various parameters. The amount of material removed was determined by measuring the wafer mass before and after polishing. Variations in temperature and slurry pH did not produce significant changes in the measured removal rates. Higher polishing pressures resulted in increased material removal rates from 200 to 500 Å/hr but also produced excessive polishing pad damage. Variations in pad rotational speeds produced the largest changes in material removal rates, from around 200 to around 2000 Å/hr for rotational speeds between 60 and 180 rpm, but the variations were non-linear and somewhat inconsistent. This CMP formula is shown to consistently produce damage free surfaces but the optimum removal rate is slow.