BTA与TT-LYK对铜CMP缓蚀效果和协同效应研究

在铜化学机械抛光中,由于典型缓蚀剂苯并三氮唑(BTA)对铜表面化学保护作用非常强烈,造成铜去除速率过低的现象。为了获得更好的缓蚀效果和铜表面质量,在近中性溶液中,对BTA缓蚀剂和新型缓蚀剂2,2′-[[(甲基-1H-苯并三唑-1-基)甲基]亚氨基]双乙醇-(TT-LYK)的缓蚀效果进行比较,并对2种缓蚀剂的复配效果进行研究。结果表明：在近中性溶液中,BTA和TT-LYK均可以有效抑制铜表面腐蚀;2种缓蚀剂复配后具有协同作用,添加到抛光液中可得到更好的铜表面质量和更低的粗糙度,这可能是由于2种缓蚀剂的钝化膜类别相似,使得在一种缓蚀剂形成配合物的基础上,另一种缓蚀剂对生成的钝化膜进行补充,使得双层钝化膜更致密,能更好地保护铜表面不受腐蚀。     

聚苯乙烯(PS)颗粒抛光液特性对铜表面化学机械抛光的影响

铜互连与低-k介质在集成电路制造中的应用对表面平坦化提出更高的要求。为改善铜层化学机械抛光(Cu-CMP)效果,将聚苯乙烯(PS)颗粒应用于铜的化学机械抛光液,分析PS颗粒抛光液中氧化剂、络合剂、pH值、粒径及颗粒含量对铜的化学机械抛光性能的影响,并通过静态腐蚀及电化学手段对PS颗粒在抛光液中的化学作用进行了分析。实验结果表明,当以过氧化氢(H2O2)为氧化剂,氨基乙酸(C2H5NO2)为络合剂时,优化后的PS颗粒抛光液取得了较高的铜抛光去除速率,达到1μm/min,同时发现PS颗粒的加入增强了抛光液的化学腐蚀作用。     

预膜时间、腐蚀温度和介质流速对油井管缓蚀剂缓蚀性能的影响

采用咪唑啉类缓蚀剂对P110S油管钢进行预膜处理和腐蚀试验,研究了预膜时间(0.54h)、腐蚀温度(30120℃)和介质流速(212m·s~(-1))对缓蚀性能的影响。结果表明:随缓蚀剂含量增加和预膜时间延长,缓蚀率增大,油管钢表面成膜效果提高;缓蚀剂质量浓度为300mg·L~(-1),预膜时间为2h时的缓蚀效果较好;随腐蚀温度升高,缓蚀剂的缓释率降低,预膜2h试样的耐腐蚀性能先降低,当温度升到80℃时耐腐蚀性最差,缓蚀剂开始失效;随介质流速增大,预膜2h试样的腐蚀速率逐渐增大;当介质流速高于10m·s~(-1)时,预膜试样发生严重腐蚀,该缓蚀剂不再适用。     

铜电致化学抛光抛光液的成分及其作用

电致化学抛光是通过电化学反应生成刻蚀剂并利用扩散控制反应实现工件表面无应力抛光的新方法,抛光液的特性则是实现扩散控制反应和可控去除的关键因素。分析电致化学抛光的基本原理,并根据理论模型提出了抛光液所应具备的基本条件。针对铜的电致化学抛光,提出以FeSO_4为电活性中介体,H_2SO_4为p H调节剂,BTA为侧向电子传导抑制剂的抛光液。通过使用XRD以及XPS等表征手段对加工后的表面进行分析,研究了铜抛光液中的p H调节剂H_2SO_4以及侧向电子传导抑制剂BTA的作用机理。研究结果表明,pH调节剂H_2SO_4的主要功能为去除Cu表面的氧化层,从而促进刻蚀反应的进行,而BTA则通过吸附于铜工件表面,从而有效地抑制了加工过程中的侧向电子传导。     

HCl-（NH4）2S2O8体系抛光液中钌的化学机械抛光研究

金属钌(Ru)有可能作为集成电路中铜互连阻挡层材料,作为阻挡层必须具有低的表面粗糙度。化学机械抛光技术已经成为集成电路制造中实现局部平面化和全局平面化的关键技术,因此对钌的化学机械抛光研究具有重要意义。利用自制抛光液,研究了在HCl-(NH4)2S2O8体系抛光液中盐(KCl)的浓度、络合剂浓度、pH值和抑制剂(BTA)等对钌的去除速率的影响。实验发现,在HCl-(NH4)2S2O8体系抛光液中,金属钌在1wt.%SiO2、1wt.%过硫酸铵、1wt.%酒石酸、1mmol/L BTA和10mmol/L KCl,pH值为9.0的抛光液中,抛光速率为10.8nm/min。电化学实验发现,在1wt.%SiO2、1wt.%过硫酸铵、1wt.%酒石酸、1mmol/L BTA和1mmol/L KCl,pH值为4.0的抛光液中,金属钌表面化学反应受抑制;在1wt.%SiO2、1wt.%过硫酸铵、1wt.%酒石酸、1mmol/L BTA和1 mmol/L KCl,pH值为9.0的抛光液中,金属钌表面钝化膜较致密、较厚。     

瓜儿豆胶接枝AMPS在CO_2环境中对J55钢的缓蚀作用

通过使用瓜儿豆胶和2-丙烯酰氨基-2-甲基丙磺酸为原料合成了瓜儿豆胶接枝AMPS(GGAMPS),并通过傅里叶红外光谱、失重法、电化学方法和扫描电子显微镜等方法考察其在3.5%NaCl的饱和CO_2溶液中对J55钢片的缓蚀作用及其表面形貌,并通过等温吸附模型研究了GG-AMPS在J55钢表面的吸附类型。结果表明,GG-AMPS对J55钢在含3.5%NaCl的饱和CO_2溶液中具有一定的缓蚀作用,能够有效抑制J55钢的腐蚀;其缓蚀效率随着缓蚀剂含量的增大而提高,且浓度一定时,温度升高,缓蚀效率逐渐下降;当加入800mg/L缓蚀剂时,缓蚀效率分别根据电化学阻抗谱和极化曲线计算所得达到了80.40%和89.23%;通过扫描电子显微镜(SEM)也表明,GG-AMPS的缓蚀效果良好;该缓蚀剂在J55钢表面的吸附是自发过程,主要为物理吸附。     

不同氧化剂对6H-SiC化学机械抛光的影响

选用胶体SiO₂纳米颗粒为磨粒,研究不同pH值条件下高锰酸钾和双氧水两种氧化剂对6H-SiC晶片化学机械抛光的影响,并使用原子力显微镜观察抛光后表面质量。采用Zeta电位分析仪分析溶液中胶体SiO₂颗粒的Zeta电位,采用X射线光电子能谱分析SiC抛光表面元素及其化学状态。结果表明：SiC晶片的材料去除率随pH值变化而变化,采用高猛酸钾抛光液抛光时,材料去除率在pH 6时达到峰值185 nm/h,R_a为0.25 nm;采用双氧水抛光液抛光时,材料去除率在pH 8时达到峰值110 nm/h,R_a为0.32 nm。pH值低于5时,电负性的SiO₂颗粒会通过静电作用吸附在带正电的SiC表面,抑制SiC晶片表面原子的氧化及去除,降低材料去除率;pH值高于5时,SiO₂颗粒在双氧水抛光液中的静电排斥力弱于高锰酸钾抛光液中静电排斥力,从而影响了SiO₂颗粒的分散性能,降低了抛光效果。采用高锰酸钾抛光液抛光后,SiC晶片表面的Si-C氧化产物含量（Si-C-O、Si₄C_4-xO₂和Si₄C₄O₄）较高,高锰酸钾抛光液的氧化能力较强。     

单晶SiC化学机械抛光液化学反应参数研究

选择影响化学机械抛光化学反应速率的参数:催化剂浓度、氧化剂浓度、抛光液的pH值、抛光液温度等进行了试验,研究了它们对基于芬顿反应的单晶SiC化学机械抛光效果的影响规律。发现只有当H_2O_2浓度高于20%、Fe_3O_4浓度高于1.25%时,增大H_2O_2、Fe_3O_4浓度,材料去除率才会显著越高,此时材料去除速率由化学液腐蚀速度与磨料机械去除速度共同决定;低于此范围时由磨料的机械作用决定。温度升高会加速H_2O_2分解,抑制羟基自由基·OH的生成,减缓化学腐蚀,降低材料去除率。当Fe_3O_4浓度、H_2O_2浓度、pH值、抛光液温度分别为1.25%、15%、7、41℃时,化学腐蚀与机械去除的协调性及磨料的分散性较好,表面粗糙度最低;当它们分别为5%、25%、9.3、15℃时,材料去除率最高。     

集成电路钴化学机械抛光缺陷控制的研究进展

钴(Co)因拥有较低的电阻率、良好的热稳定性、与Cu黏附性好等优点,可以替代钽(Ta)成为铜(Cu)互连结构的阻挡层;当特征尺寸减小到10 nm后,由于Co良好的抗电迁移能力,可以在很薄的阻挡层上实现无空隙填充,作为理想的互连金属候选材料,表现出了巨大的应用潜力。但由于Co的反应活性较强,以及不同金属材料之间的腐蚀电位差异,在化学机械抛光(CMP)过程中容易形成点蚀和电偶腐蚀缺陷,严重影响器件的性能,而成为研究的热点。综合分析近年来关于钴CMP过程中表面缺陷的产生及控制的相关研究,重点分析抛光液中的络合剂、缓蚀剂等成分对于钴表面缺陷的产生以及控制的作用机制;指出在碱性环境下,选择合适的缓蚀剂和络合剂以及利用不同缓蚀剂的协同作用,可以有效控制点蚀缺陷的发生,并指出量子化学可从分子层面上定性定量地分析抛光液中各试剂的相互协同机制,为抛光液的设计提供理论支撑。     

江西研制成功新型稀土铜缓蚀剂

近日，由江西理工大学科研人员开发的“稀土铜缓蚀剂及其表面处理工艺”经国家知识产权局批准，获得国家专利。 据介绍，该校研制成功的稀土铜缓蚀剂包括混合稀土盐、磺基水杨酸、苯丙三氮唑、柠檬酸和水等配方。铜缓蚀剂对环境无危害，缓蚀效率高，原料易得，成本较低，表面处理工艺操作简单，溶液成分稳定且维护调整方便，能有效提高稀土矿产资源的可持续发展利用效率。     

Material Removal Mechanism of Copper CMP from a Chemical�CMechanical Synergy Perspective

The material removal in chemical?Cmechanical planarization/polishing (CMP) of copper involves both chemical and mechanical effects. The roles of chemical corrosion, abrasive wear, and their synergistic effects on the material removal mechanism were studied by electrochemical analysis and nano-scratching method using atom force microscopy, respectively. Combining with the results of CMP experiments, dominant factors (chemistry and mechanics) in slurries within the range of pH 3.0?C10.0 were assessed. Consequently, a removal mechanism map of copper CMP depending on pH values was constructed. In the alkaline slurry, the wear?Ccorrosion effect predominated in the material removal at pH 8.0 and 9.0; while the copper removal mechanism changed to corrosion?Cwear action in the acidic slurry from pH 4.0 to 6.0, and good surface quality was also obtained. The results and the strategies provide thorough understanding of the material removal mechanism and further optimization of the CMP process.     

铜互连CMP工艺中缓蚀剂应用的研究进展*

抛光液是铜互连CMP的关键要素之一,在CMP中每种成分发挥不同的功能,其中缓蚀剂的选择及性能对抛后的表面质量会产生直接影响。对近年来铜互连CMP中各类缓蚀剂的研究进展以及缓蚀剂与不同类型添加剂间的复配协同进行归纳总结,同时介绍缓蚀剂与不同类型添加剂间的作用机制。最后对未来铜互连CMP中缓蚀剂的应用前景进行展望,指出绿色环保的铜互连CMP缓蚀剂的开发,通过缓蚀剂的复配协同作用以提高抛光质量,以及从微观角度进一步揭示缓蚀剂的作用机制是未来的研究方向。     

Effects of Chemical Additives of CMP Slurry on Surface Mechanical Characteristics and Material Removal of Copper

Investigations were performed to study the effects of H₂O₂ as oxidant, glycine as complexing agent, and benzotriazole (BTA) as inhibitor on surface mechanical characteristics and material removal of copper. Etch rates and surface roughness of Cu samples were measured in the presence of these chemicals at pH 4 or pH 10 under static conditions. Scanning electron microscopy images revealed that the surface of etched copper samples became layered and porous. Scratching experiments were carried out on the etched surface to investigate effects of these chemicals on mechanical removal of copper using atomic force microscopy. It was observed that the scratched depth of these etched Cu samples was higher than that of Cu metal. The addition of glycine enhanced chemical dissolution and mechanical removal greatly. However, the further addition of BTA made both of them decreased, suggesting BTA not only inhibitor of chemical dissolution, but also inhibitor of mechanical removal. In most cases, the measured hardness values of etched copper surface were slightly higher than that of Cu metal. These results indicated that changes of surface structure were the primary reason for increase of mechanical removal of copper, but not changes of copper surface nanohardness.     

Tribo-chemical Behavior of Copper in Chemical Mechanical Planarization

Chemical mechanical planarization/polishing (CMP) of copper has emerged as an important component in semiconductor processing. It involves both chemical and mechanical effects, consisting of several steps such as passivation, film dissolution, chemical corrosion, and abrasive abrasion. It is important to understand the individual steps in the removal process. In this paper, investigations were focused on the tribo-chemical behavior of copper in hydrogen peroxide solution at different pH values. The repassivation current and friction coefficient were measured in situ as a function of time. The compositions of unworn and worn surfaces after the tribocorrosion experiments were also analyzed by Raman spectra. The copper exhibited a tendency of repassivation during the potentiostatic tests; furthermore, the repassivation kinetics varied with the surface species and the quantity of passive films formed at different pH values. The results indicate that both relatively high material removal rate and good surface quality may be achieved in the weak acidic solution during CMP.     

阴离子表面活性剂及复配对阻挡层抛光液性能的影响

为提高铜互连化学机械抛光(CMP)后表面质量，在抛光液中需引入适当的表面活性剂以改善磨料的稳定性以及CMP后铜的表面粗糙度。研究了十二烷基硫酸铵(ADSA)、脂肪醇聚氧乙烯醚硫酸铵(AESA)、直链烷基苯磺酸(LABSA)3种不同阴离子表面活性剂，以及非离子表面活性剂脂肪醇聚氧乙烯醚(AEO-9)和LABSA复配表面活性剂对钽阻挡层抛光液润湿性、分散性以及对材料去除速率的影响。通过接触角测量仪、纳米粒度仪、扫描电镜和原子力显微镜测试表面张力、接触角、大颗粒数、粒径分布以及CMP后铜的表面粗糙度，并分析复配表面活性剂的作用机制。结果表明：抛光液中加入LABSA后，因其具有直链型结构，抛光液的润湿性和分散性效果最好，抛光后铜表面的粗糙度最低；AEO-9和LABSA进行复配，相较于单一的LABSA,抛光液的润湿性、分散性、稳定性和抛光后铜表面粗糙度均有所改善，体积分数0.1%LABSA+0.1%AEO-9的复配表面活性剂性能最优，CMP后铜表面粗糙度降至0.7 nm。     

An empirical approach to explain the material removal rate for copper chemical mechanical polishing

In this paper, an empirical expression was deduced based on the experimental data for material removal rate of copper chemical mechanical polishing. The parameters of this expression includes the initial chemical corrosion rate(MRR₀), the corrosion inhibition efficiency(k) and the mechanical abrading rate(MRR_M). The deduced empirical expression revealed that under certain slurry systems, the corrosion inhibition efficiency may always keep unchanged, which may be useful to characterize the inhibition properties of different inhibitors.     

Electrochemical Analysis of the Slurry Composition for Chemical Mechanical Polishing of Flexible Stainless-Steel Substrates

The surface quality of the stainless steel affects the efficiency of flexible photovoltaics. Chemical mechanical polishing (CMP) is a finishing process that is used to prepare substrates for electronic devices. The CMP slurry composition is an important factor because additives in the slurry generally improve the polishing performance. However, it is limited to find the optimum conditions for the slurry by only experimental approaches. Thus, this study uses electrochemical analysis and friction monitoring to examine the effects of the abrasive, oxidizer, chelating agent, and pH. Electrochemical and monitoring analysis are useful for validating predictions and understanding interactions between the slurry and the stainless steel surface. Good correspondence was found between the predictions and the polishing results in more accurate. The corrosion rate (CR) obtained from the potentiodynamic polarization curve is proportional to the experimental results, as is the behavior of the curve and the coefficient of friction (COF). After only 3 min CMP, the best performing slurry (abrasive 39 wt %, oxalic acid 1 wt %, H₂O₂ 0.03 wt %, pH 1.5) improved the surface quality of 304 stainless steel by 4 nm. As a result, the proposed methods could help reduce the risks involved in stainless steel CMP slurry and these results could provide a reference for optimizing CMP slurry for flexible 304 stainless steel substrates.     

表面活性剂在集成电路多层布线CMP工艺中的应用研究

随着集成电路(IC)特征尺寸不断缩小,集成电路多层布线加工精度面临更高的要求,而化学机械抛光(CMP)凭借化学腐蚀和机械磨削的耦合协同作用,成为实现晶圆局部和全局平坦化的唯一可靠技术。抛光液作为CMP工艺中关键要素之一,其主要成分表面活性剂的选择以及含量会严重影响晶圆的表面质量。介绍表面活性剂的特性及其类型,回顾近年来国内外表面活性剂在集成电路多层布线相关材料CMP中的应用及作用机制,归纳总结得出表面活性剂在CMP过程中可以起到缓蚀保护、增强润湿、分散磨料、去除晶圆表面残留污染等多种作用,具有广泛的应用领域。同时,对表面活性剂在CMP中的应用前景进行了展望。     

无磨料化学机械抛光的研究进展

无磨料化学机械抛光(AFP)技术克服传统化学机械抛光(CMP)易产生凹陷、腐蚀和微观划痕等表面损伤的特点,成为解决半导体晶片上Cu膜表面平坦化的重要技术;AFP已广泛用于铜大马士革层间互连及其他材料的加工.综述了AFP技术的研究现状,指出了AFP急待解决的技术和理论问题,并对其发展趋势进行展望.