蓝宝石衬底的化学机械抛光工艺研究

系统地分析了蓝宝石抛光工艺过程的性能参数,通过大量实验总结出了其影响因素并提出了优化方案。结果表明,采用粒径为40nm、低分散度的SiO2溶胶磨料并配合以适当参数进行抛光,可以获得良好的表面状态和较高的去除速率,能够有效提高蓝宝石表面的性能及加工效率。     

蓝宝石衬底化学机械抛光的机理研究

利用磨料为SiO2的碱性抛光液对蓝宝石衬底材料进行了化学机械抛光，并对蓝宝石衬底化学机械抛光（简称CMP）的机理进行了深入的研究，指出了蓝宝石CMP的主要的动力学过程，并详细分析了影响各动力学过程的诸要素。结果表明，蓝宝石衬底的CMP过程是一个复杂的多相反应过程，是化学作用与机械作用互相加强和促进的过程，影响它的各要素间既相互促进，又相互制约。     

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。     

碱性纳米SiO_2溶胶在化学机械抛光中的功能

纳米SiO2是一种性能优越的功能材料,化学机械抛光(CMP)过程的精确控制在很大程度上取决于对纳米SiO2功能的认识。但是目前对碱性纳米SiO2在CMP过程中的功能还没有完全弄清楚,探讨它在CMP中作用是提高CMP技术水平的前提。纳米SiO2溶胶的表面效应使其表面存在大量的羟基,在CMP过程中纳米SiO2表面羟基与碱反应生成硅酸负离子,硅酸负离子再与硅反应来降低纳米SiO2的表面能量,同时达到除去硅的目的。综上所述,碱性纳米SiO2在CMP的过程中不仅起到了磨料的作用,同时参加了化学反应,在此基础上提出了在碱性条件下纳米SiO2与硅的反应机理。     

混合磨料对LED用蓝宝石衬底CMP质量的影响

分析了混合磨料在蓝宝石衬底化学机械抛光(CMP)过程中的作用机理,并对比了SiO2水溶胶磨料和SiO2与Al2O3混合磨料对蓝宝石衬底去除速率的影响.研究表明,在主磨料SiO2水溶胶中加入浓度为20mL/L同粒径纳米级的Al2O3可以使CMP过程中的化学作用与机械作用达到相互平衡,使抛光去除速率得到明显提高.在距抛光终点5～10min通过调整工艺参数与抛光液配比,使表面粗糙度由2.32nm降至0.236nm.     

单晶金刚石机械研磨与化学机械抛光工艺

单晶金刚石在工业、国防等领域的应用日益广泛,对其加工表面质量的要求不断提高,使用常温低压的化学机械抛光可实现金刚石的超光滑低损伤表面加工.通过理论分析及实验研究得出,使用硅酸盐玻璃材质研磨盘进行研磨加工,可以将金刚石表面粗糙度Ra降至15~25 nm,且无明显机械划痕;在2 MPa压力及室温环境下进行单晶金刚石化学机械抛光实验,优选出Fenton试剂酸性水基抛光液,使用该抛光液抛光单晶金刚石可获得粗糙度Ra值4 nm以下的光滑表面.     

镁合金化学机械抛光中缓蚀剂的研究

基于碱性氧化铈抛光液体系,研究了磷酸氢二纳和氟化钾两种缓蚀剂对镁合金缓蚀影响的基本规律。采用扫描电镜、X射线光电子能谱和电化学实验分析了化学机械抛光中镁合金表面微观形貌和缓蚀机理。发现:1%(质量分数)磷酸氢二纳电荷转移电阻最大为7481Ω·cm-2,电流密度最小为0.01441mA/cm~2,具有最佳缓蚀能力。Na_2HPO_4在镁合金表面生成完整的钝化膜,具有很好的缓蚀能力。其缓蚀机理是:Na_2HPO_4在镁合金表面生成MgHPO_4,可以阻挡腐蚀介质向镁合金表面靠近,有效抑制了镁合金基片的腐蚀。     

氧化铝颗粒的表面改性及其在C平面(0001)蓝宝石衬底上的化学机械抛光(CMP)性质

为了提高氧化铝颗粒的CMP性能, 本工作探索了一种合适的改性方法。同时, 为了改善其化学机械性能, 通过与其表面羟基的硅烷化化学反应和与Al和仲胺的络合两种作用, 用N-(2-氨基乙基)-3-氨基丙基三甲氧基硅烷表面改性氧化铝颗粒。本工作给出了化学反应机理, 即N-(2-氨基乙基)-3-氨基丙基三甲氧基硅烷接枝到氧化铝表面。通过傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)表征了改性氧化铝颗粒的组成和结构。结果表明: N-(2-氨基乙基)-3-氨基丙基三甲氧基硅烷已被成功地接枝到氧化铝颗粒的表面, 导致改性比未改性的氧化铝颗粒具有更好的化学和机械性能。测试了未改性和改性的氧化铝颗粒在蓝宝石基底上的CMP性能。结果显示: 改性氧化铝颗粒比未改性氧化铝颗粒有更高的材料去除速率和更好的表面质量。即, 改性氧化铝颗粒在pH=10时比未改性氧化铝颗粒在pH=13.00时表现出更高的材料去除率, 这将为减少设备腐蚀提供新思路。     

不同磨料对微晶玻璃化学机械抛光的影响

为了提高微晶玻璃化学机械抛光(CMP)的材料去除速率(MRR),降低其表面粗糙度,利用自制的抛光液对微晶玻璃进行化学机械抛光,研究了4种含不同磨料(Si O2、Al2O3、Fe2O3、Ce O2)的抛光液对微晶玻璃化学机械抛光MRR和表面粗糙度的影响.利用纳米粒度仪检测抛光液中磨料的粒径分布和Zeta电位,利用原子力显微镜观察微晶玻璃抛光前后的表面形貌.实验结果表明,在相同条件下,采用Ce O2作为磨料进行化学机械抛光时可以获得最好的表面质量,抛光后材料的表面粗糙度Ra=0.4 nm,MRR=100.4 nm/min.进一步研究了抛光液中不同质量分数的Ce O2磨料对微晶玻璃化学机械抛光的影响,结果表明,当抛光液中Ce O2质量分数为7%时,最高MRR达到185 nm/min,表面粗糙度Ra=1.9 nm;而当抛光液中Ce O2质量分数为5%时,MRR=100.4 nm/min,表面粗糙度最低Ra=0.4 nm.Ce O2磨料抛光后的微晶玻璃能获得较低表面粗糙度和较高MRR.     

乳酸体系抛光液中锇的化学机械抛光

本文研究了乳酸(HL)体系抛光液中金属锇的化学机械抛光(CMP)行为,采用电化学分析方法和X射线光电子能谱仪(XPS)分析氧化剂和腐蚀抑制剂的作用机理,利用原子力显微镜(AFM)观察抛光前后锇的表面形貌.结果表明,当抛光液仅含有H2O2时,金属锇表面腐蚀不明显;在一定浓度范围内H2O2浓度的增加可以提高金属锇表面的腐蚀速度,但是不利于金属锇表面钝化膜的形成.当抛光条件为:压力为6.895 kPa,转速为50 r/min,抛光液流量为50 mL/min,pH值为5.0;抛光液组成为:SiO2质量分数为1%,HL质量分数为1%,H2O2质量分数为3%时,得到最大去除速率为23.34 nm/min,表面粗糙度Ra为6.3 nm,而将缓蚀剂BTA加入到抛光液后,在同样的抛光条件下得到的锇表面粗糙度更低,表面粗糙度Ra达到2.1 nm.     

Treating chemical mechanical polishing (CMP) wastewater by electro-coagulation-flotation process with surfactant

The effect of surfactants on the treatment of chemical mechanical polishing (CMP) wastewater by electro-coagulation-flotation (ECF) process was studied. Two surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) were employed in this study to compare the effect of cationic (CTAB) and anodic (SDS) surfactants on ECF. The cationic surfactant can enhance the removal of the turbidity, but anodic surfactant cannot. It can be explained by the hetero-coagulation theory. Moreover, the addition of CTAB in CMP wastewater can reduce the sludge volume and the flotation/sedimentation time in ECF process. The residual turbidity and dissolved silicon dropped with the increase of charge loading. No CTAB pollution problem exists after the ECF process.     

An optimization of tungsten plug chemical mechanical polishing (CMP) using different consumables

The continuous shrinkage of integrated circuit devices provides the advantage of having more electrical functions on the smaller chips. However, it has posed severe challenges to the manufacturing of these products. In patterning steps, the depth of focus becomes small, due to the nature of patterning small features and is aggravated by the presence of step height differences in the exposure field. When the aspect ratio of holes increases, aluminum, which has been the choice of metal to fill holes, no longer effectively fills small holes. On some occasions, discontinuous aluminum exists in the holes, resulting from poor step coverage. Tungsten (W), on the other hand, can satisfactorily fill small holes by chemical vapor deposition and thus fills a need to replace aluminum as an electrical connector plug for layers separated by this plug. Chemical mechanical polish (CMP) has been used recently to planarize substrates and improve the depth of focus, as in the case of hole patterning. It is also used to prepare the metal plug effectively. CMP processing involves various parameters, such as machine configuration, slurry chemistry and formulation, polishing pad configuration, pad hardness, etc. Although the mechanism is not fully understood, these parameters are known to significantly influence the degree of planarization, contamination, defects, etc. In this paper we explore the effects of consumables used in the W-CMP process on the control of several problems, such as recessed plug, dishing and oxide erosion, etc. Based on our findings, we implement a two-step W-CMP process to improve the qualities of the polished wafers. The first step involves a proper combination of slurry and pad to polish most of the bulk tungsten with a high polish rate. The second step uses the same pad, slurry and a proprietary additive to slowly polish the remaining tungsten. In this way, we are able to obtain a workable W-CMP process. © 2001 Kluwer Academic Publishers     

Macroscopic and microscopic investigation on chemical mechanical polishing of sapphire wafer

Sapphire (alpha-Al2O3) is an important ceramic material that is widely used in substrate material for electronics. We investigate the chemical reaction layer on a sapphire wafer using X-ray photoelectron microscopy (XPS) and atomic force microscopy (AFM). The frictional characteristics of sapphire chemical mechanical polishing (CMP) was studied using in-situ friction force monitoring system. From XPS analysis and AFM experiment, a chemically-reacted layer was verified on the sapphire surface through a chemical reaction between the sapphire and chemicals in a slurry. During sapphire CMP, the friction force mainly depended on the applied pressure. The material removal efficiency per unit friction energy in sapphire CMP was 6.18 nm/kJ.     

纳米集成电路中镍基CMP工艺(英文)

机械化学抛光(CMP)工艺普遍应用于纳/微机械制造中,特别是复杂的层状结构MEMS.鉴于镍及镍基合金具有高的沉积速率、可控的薄层应力、低的电阻和制备温度以及机械特性,本文研究了镍及镍基合金用于具有运动结构的纳/微EMS器件的可行性,重点研究了基于镍的CMP工艺,其电化学势的变化用电动势极化曲线进行了分析,镍膜层表面用XPS和SEM进行了分析,结果表明:镍的刻蚀速率随着双氧水和缓蚀剂EDTA浓度中加而增加,在双氧水浓度在1%左右时达到最大.其刻蚀过程的动态和静态的电动势极化曲线具有明显不同,XPS分析表明:无双氧水的刻蚀液薄膜表面主要是形成NiO,存在H2O2的刻蚀液薄膜表面主要是形成Ni(OH)2,表面的镍所处的电化学状态是影响刻蚀行为的主要原因.     

The effects of chemical polishing on the strength of sapphire whiskers

Tensile tests at 20 C have been carried out on forty-four sapphire whiskers after chemical polishing in hot orthophosphoric acid. The orientations tested were 0001, 11¯20, 10¯10, and 10¯11. The results show that chemical polishing increases the strength of large whiskers by a factor of up to 10, but not the strength of small ones. Good correlation is obtained between fracture strength, _f, and whisker diameter,d. The relevant size-strength equations, _f=Kd ^m l ⁿ (wherel is gauge length, andK, m, andn are constants depending on whisker orientation), predict strengths in good agreement with the theoretical strength of sapphire at unit-cell dimensions and with the measured strengths of macroscopic flame-polished crystals.The observations are contrasted with those for unpolished sapphire whiskers [1]. They show a transition in the fracture nucleation mechanism of unpolished whiskers at a certain stress.In unpolished, A-type (11¯20 and 10¯10) whiskers, with _f<1000 kg/mm², fracture initiates at surface flaws, and strength is dependent on surface area. But, for whiskers with _f>1000 kg/mm₂, and for all polished whiskers (both A and C type), fracture is due to dislocation pile-ups or interactions, and strength is dependent only upon diameter. In unpolished, C-type (0001) whiskers, however, with _f<800 kg/mm₂, fracture initiates at surface flaws which are related to whisker diameter; while, for _f> 800 kg/mm², it occurs at dislocation pile-ups or interactions and is again related to diameter. In contrast, therefore, to A-type whiskers, the strength of C-type whiskers is always diameter-dependent, although there is a clear transition in the size-strength curve at _f800 kg/mm².     

Chemical mechanical polishing (CMP) of on-axis Si-face 6H-SiC wafer for obtaining atomically flat defect-free surface

Due to its high mechanical hardness and excellent chemical inertness, SiC single-crystal wafer is extremely difficult to realize effectively removed total planarization. Owing to crystalline polarity and anisotropy, material removal rate (MRR) on Si-face (0001) of SiC wafer is significantly lower than C-face (000 $ \bar{1} $ ) for a defect-free surface. In the paper, the slurry containing hydrogen peroxide (H₂O₂), potassium hydroxide and abrasive colloidal silica, is introduced to chemical mechanical polishing (CMP) of on-axis Si-face 6H-SiC wafer, resulting in acquiring high MRR with 105 nm/h, and atomically flat defect-free surface with atomic step-terrace structure and roughness of 0.0667 nm by atomic force microscope (AFM), in order to satisfy further demands of electronic device fabrication towards substrate wafer performance. The effects of the three ingredients in the slurry towards MRR of SiC wafer, polished surface quality and coefficient of friction in polishing process are studied. Optical microscope, optical interferometry profiler and AFM are used to observe the polished surface. In addition, the CMP removal mechanism of SiC wafer and the formation of ultra-smooth surface are discussed.     

A chemical mechanical polishing model incorporating both the chemical and mechanical effects

A comprehensive model for the material removal in a chemical mechanical polishing (CMP) process is presented in which both chemical and mechanical effects are taken into consideration. The chemical effects come into play through the formation of chemically modified surface layer on the wafer surface that, in turn, is removed mechanically by the plastic deformation induced by slurry particles. This model describes the influence of most, if not all, variables involved in the CMP process including slurry characteristics (solid loading, particle size and distribution, modulus), pad properties (modulus, hardness, asperity sizes and distribution) and processing conditions (down-pressure, velocity). Although more elaborate experimental verification of the model is yet to follow, this model appears to be capable of explaining many experimental observations on both oxide and metal CMP that, otherwise, could not be explained properly.