The removal of nanoparticles from sub-micron trenches using megasonics

The removal of nanoparticles form patterned wafers is one of the main challenges facing the semiconductor industry. In this paper, the removal of 100 and 200 nm polystyrene latex (PSL) particles from silicon trenches was investigated. Red fluorescent PSL particles were utilized in the cleaning experiments and were counted using fluorescent microscopy. All the experiments were conducted in a single wafer megasonic tank using deionized water (DI). Trenches were fabricated with widths varying from 200 nm to 2 μm and with an aspect ratio of one. Results show that removal of particles from larger trenches is faster compared to smaller trenches and that megasonics power is more important in the removal process than cleaning time.     

The removal of deformed submicron particles from silicon wafers by spin rinse and megasonics

In order to successfully clean particulate contamination from wafer surfaces, it is necessary to understand the adhesion and deformation between the particles and the substrate in contact. The adhesion and removal mechanisms of deformed submicron particles have not been addressed in many previous studies. Submicron polystyrene latex particles (0.1–0.5 μm) were deposited on silicon wafers and removed by spin rinse and megasonic cleanings. Particle rolling is identified as the major removal mechanism for the deformed submicron particles from silicon wafers. Megasonics provides larger streaming velocity because of the extremely thin boundary layer resulting in a larger removal force that is capable of achieving complete removal of contamination particles.     

抛光液中各组分对Co CMP性能的影响

钴(Co)的化学机械抛光(CMP)要求有较高的去除速率(大于100 nm/min)和洁净平整的表面。采用新型弱碱性抛光液,研究不同成分(如过氧化氢(H₂O₂)、1,2,4-三氮唑(TAZ)、异辛醇聚氧乙烯醚(JFCE))对Co CMP性能的影响。结果表明,抛光液中H₂O₂体积分数为0.4%、pH值为8、甘氨酸(GLY)浓度为0.266 mol/L时,Co的去除速率最大,为763.53 nm/min。为了缓解Co表面的化学腐蚀,加入0.022 mol/L的TAZ作为抑制剂和体积分数为1.3%的JFCE作为表面活性剂后,Co的去除速率得到有效抑制,为489.74 nm/min。对抛光前后的Co表面进行原子力显微镜(AFM)测试,结果表明,Co表面湿润性增加,表面粗糙度明显下降。研究结果对Co布线的工业应用具有一定的指导意义。     

锈蚀表面的激光清洗及其元素组成分析

采用波长1064 nm高重频高能量激光清洗设备,研究了激光清洗碳钢表面锈蚀时工艺参数对除锈效果的影响,分析了激光清洗锈蚀表面、微区、线和点处的元素组成以及相对含量。结果发现:脉冲激光在优化参数下能将碳钢表面的锈蚀完全清洗干净,激光清洗锈蚀表面、微区、线和点处都没有发现氧元素的存在,表明脉冲激光不仅能将碳钢表面的锈蚀完全清洗干净,而且在激光清洗锈蚀过程中不会发生铁元素和氧元素的化学反应,生成氧化铁膜。     

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。     

碱性Cu化学机械抛光液性能研究

在分析碱性Cu化学机械抛光液作用机理的基础上,考察了抛光液对铜晶圆电化学、表面形态、化学机械抛光去除速率等性能。结果发现:选用新研制的络合剂R(NH2)n,将Cu的氧化物、氢氧化物转化为可溶性络合Cu,实现了碱性抛光液中Cu的去除。同时发现,随着碱性抛光液质量分数的增加,淀积Cu层不仅易被腐蚀,腐蚀速率也有所增加,并且当抛光液质量分数达到63.7%(Cu3),会对Cu的腐蚀起到抑制作用。抛光后表面形态分析说明此碱性化学机械抛光液能有效改善晶圆表面粗糙度,且对Cu层平均去除速率是酸性商用抛光液的4～5倍。     

新型碱性抛光液对300mm TaN镀膜片CMP效果评估

TaN由于其良好的性能广泛用于布线铜与介质之间的阻挡层和黏附层.在对直径为300 mm的TaN镀膜片进行化学机械抛光(CMP)后,对比并分析了两种碱性抛光液对TaN去除速率、片内非均匀性、去除速率选择性和表面粗糙度的影响.结果表明,经过自主研发且不合氧化剂的碱性阻挡层抛光液抛光后,TaN的去除速率为40.1 nm/min,片内非均匀性为3.04％,介质、TaN与Cu的去除速率之比为1.69∶1.26∶1,中心、中间以及边缘的表面粗糙度分别为0.371,0.358和0.366 nm.与商用抛光液抛光结果相比,虽然采用自主研发的抛光液抛光的去除速率低,但片内非均匀性以及选择性均满足商用要求,且抛光后TaN表面粗糙度小,易清洗,无颗粒沾污.综合实验结果表明,自主研发的高性能碱性抛光液对TaN镀膜片具有良好的抛光效果,适合工业生产.     

磨料对硒化锌雾化施液化学机械抛光的影响

采用雾化施液化学机械抛光（CMP）的方法,以材料去除速率和表面粗糙度为评价指标,选取最适合硒化锌抛光的磨料,通过单因素实验对比CeO2、SiO2和Al2O3三种磨料的抛光效果。结果显示:采用Al2O3抛光液可以获得最高的材料去除率,为615.19nm/min,而CeO2和SiO2磨料的材料去除率分别只有184.92和78.56nm/min。进一步分析磨料粒径对实验结果的影响规律,表明100nm Al2O3抛光后的表面质量最佳,粗糙度Ra仅为2.51nm,300nm Al2O3的去除速率最大,达到1 256.5nm/min,但表面存在严重缺陷,出现明显划痕和蚀坑。在相同工况条件下,与传统化学机械抛光相比,精细雾化抛光的去除速率和表面粗糙度与传统抛光相近,但所用抛光液量约为传统抛光的1/8,大大提高了抛光液的利用率。     

非离子表面活性剂在阻挡层CMP后清洗中去除颗粒作用的研究

本文对非离子表面活性剂在阻挡层CMP后清洗中对颗粒的去除作用进行了研究。实验过程中,通过改变活性剂的浓度,在12inch多层铜布线片上进行了一系列的实验来确定最佳的清洗效果。然后对活性剂在缺陷控制、颗粒去除,以及活性剂在清洗过程中所起的负面作用等方面进行了讨论。实验结果表明,非离子表面活性剂在阻挡层CMP后清洗中根据浓度的不同所起的正面、负面作用不同,从而为阻挡层CMP后清洗过程中非离子表面活性剂的加入起到一定的指导作用。     

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。     

Material removal rate of 6H-SiC crystal substrate CMP using an alumina（Al2O3） abrasive

正The influences of the polishing slurry composition,such as the pH value,the abrasive size and its concentration,the dispersant and the oxidants,the rotational velocity of the polishing platen and the carrier and the polishing pressure,on the material removal rate of SiC crystal substrate(0001) Si and a(0001) C surface have been studied based on the alumina abrasive in chemical mechanical polishing(CMP).The results proposed by our research here will provide a reference for developing the slurry,optimizing the process parameters,and investigating the material removal mechanism in the CMP of SiC crystal substrate.     

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.     

ULSI介质CMP用大粒径硅溶胶纳米研磨料的合成及应用研究

针对超大规模集成电路多层互连结构中介质CMP抛光速率低,急需的大粒径硅溶胶研磨料,本文采用改进的粒径生长控制工艺制备介质CMP用大粒径硅溶胶,并采用TEM、激光粒度分析仪和Zeta电位测试仪等先进手段对其粒径大小、粒径分布和稳定性进行了表征。以低分散度硅溶胶纳米研磨料配制抛光浆料进行了二氧化硅介质的CMP研究,结果表明,平均粒径103．4nm的硅溶胶浆料的去除速率达630nm／min,有效解决了二氧化硅介质CMP低速率的难题。     

多层铜布线表面CMP后颗粒去除研究

针对目前清洗技术存在的问题进行了详细分析,研究了微电子材料表面污染物的来源及其危害,并介绍了表面活性剂在颗粒去除方面的作用。研究了化学机械抛光(CMP)后Cu布线片表面的颗粒吸附状态,分析了铜片表面颗粒的吸附机理。采用非离子表面活性剂润湿擦洗方法,使Cu表面的颗粒处于易清洗的物理吸附状态。利用金相显微镜和原子力显微镜(AFM)在清洗前后进行对比分析,实验采用聚乙烯醇(PVA)刷子分别对铜片和铜布线片进行清洗,发现非离子界面活性剂能够有效去除化学机械抛光后表面吸附的杂质,达到了较好的清洗效果。     

FA/O精抛液组分对Cu/Ta CMP去除速率的影响

研究了精抛液中各组分对Cu/Ta去除速率的影响.在分别考察磨料质量分数、Ⅱ型螯合剂、活性剂和双氧水等各组分对Cu/Ta去除速率的影响后,研发了磨料质量分数为2％,Ⅱ型螯合剂体积分数为0.35％,活性剂体积分数为2％,H2O2体积分数为2％的FA/O精抛液.并在MIT854布线片上进行了精抛测试.结果显示,精抛12 s之后,100-100线条处高低差从精抛前的76.7 nm降低为63.2 nm,而50-50线条处高低差从精抛前的61.3 nm降低为59.8 nm.并且,经过FA/O精抛液精抛后粗抛后产生的尖峰也有所减小,台阶趋于平坦.精抛后,100-100和50-50处的高低差均小于70 nm,能够达到产业化指标.     

碱性条件下铝CMP的机理分析及实验优化

依据铝的电化学腐蚀特性,阐明了碱性条件下铝化学机械抛光(CMP)的机理。由于铝的硬度较低,在抛光过程中容易产生微划伤等缺陷,因此首先探索出适宜铝化学机械抛光的低压条件(4 psi,1 psi=6.895 kPa)。此外,提出两步抛光的方法,在抛光初期采用压力4 psi,抛光液由质量分数为40%的纳米级硅溶胶与去离子水(DIW)以体积比1∶1配制,氧化剂(H2O2)体积分数为1.5%,FA/O I型表面活性剂体积分数为1%,调节FA/OⅡ型螯合剂pH值为11.0,获得了较高的铝去除速率(341 nm/min)。在抛光后期采用低压1.45 psi,抛光液主要成分为体积分数5%的FA/O表面活性剂,并在较大体积流量(300 mL/min)的条件下进行抛光,充分利用表面活性剂的作用,对实验方案进行优化。采用优化后的实验方案,铝表面的划伤和缺陷显著减少。     

In-process detection of microscratching during CMP using acoustic emission sensing technology

An experimental investigation on the correlation between the microscratches and the signal characteristics of acoustic emission (AE) generated during chemical mechanical planarization (CMP) has been performed. CMP experimental results from both laboratory and production line CMP machines have clearly showed that AE rms voltage in the time domain has distinctive features relating to scratching. The sensitivity of AE signals to the CMP process state change was also investigated. The results show that this AE sensing technology can be used as a tool for in-situ microscratch detection and process monitoring in CMP.     

一种有效解决Cu CMP后残留二氧化硅颗粒的清洗液

摘要：在本文中提出了一种新型有效去除二氧化硅颗粒的FA/O清洗液,其主要成分包括FA/OII型螯合剂和FA/O型活性剂。这种清洗液能够同时去除以物理和化学吸附在晶圆表面的硅溶胶颗粒。 在本文实验过程中通过改变螯合剂和活性剂的浓度, 得出最佳清洗浓度。并且,讨论了这种FA/O碱性清洗剂去除硅溶胶颗粒的机理。根据实验结果可知,FA/OII型螯合剂和活性剂都能够有效去除硅溶胶颗粒。当FA/OII型螯合剂和FA/O活性剂达到最佳配比时,这种新型清洗液能够有效去除硅溶胶颗粒。     

A lubrication model between the soft porous brush and rigid flat substrate for post-CMP cleaning

A 3D lubrication model between a soft porous brush and rigid flat surface in the post-CMP (chemical mechanical polishing) cleaning process for wafer or hard-disc surface is set up in this article. The mesh porous structure of the brush and the kinematic relations between the brush and the surface are taken into account. The flow governing equations for cleaning process are deduced with Newtonian fluids between the brush nodule and the substrate. The distributions of fluid pressure and hydrodynamic removal moment are calculated. The simulation results show that the fluid pressure has negative regions in inlet area. The removal force is depended on system parameter, location, time and particle size. The load and hydrodynamic moment increase with the increase of brush velocity and deflection of brush nodule, which is effective for cleaning. A low wafer rotation speed is recommended to keep the cleaning uniformity. The removal moment is increasing during the cleaning process. The hydrodynamic drag force decreases rapidly with decreasing of particle size. The models are coincident with the actual process and can be used as reference for designing a higher level cleaning process and the analysis of the formation of particle defect.     

硒化镉晶片的化学机械抛光

硒化镉(CdSe)的表面加工质量对CdSe基器件的性能至关重要.化学机械抛光(CMP)是一种获得高质量晶体加工表面的常用方法.为改善CdSe晶片的表面加工质量,以SiO2水溶胶配制抛光液,研究了抛光液磨料质量分数、抛光液pH值、氧化剂NaClO的质量分数、抛光盘转速和抛光时间等因素对CdSe晶片抛光去除速率和表面质量的影响,优化了CdSe的CMP工艺参数.结果表明,在优化工艺条件下,CdSe的平均去除速率为320 nm/min,晶片的抛光表面无明显划痕和塌边现象.原子力显微镜(AFM)测量结果表明,抛光后的CdSe晶片表面粗糙度为0.542 nm,可以满足器件制备要求.