化学机械抛光过程抛光液作用的研究进展

化学机械抛光(CMP)已成为公认的纳米级全局平坦化精密超精密加工技术。抛光液在CMP过程中发挥着重要作用。介绍了CMP过程中抛光液的作用的研究进展,综合归纳了抛光液中各组分的作用,为抛光液的研制和优化原则的制定提供了参考依据。     

弱碱性抛光液中铜化学机械抛光的电化学行为

在弱碱性介质里以铁氰化钾为钝化剂,对铜化学机械抛光技术（CMP）过程中的电化学行为进行了在线测试,考察了铜在无铁氰化钾存在下的极化行为及铁氰化钾浓度对腐蚀电位的影响,研究了在不同压力下铜抛光前后的腐蚀电位（φE）和腐蚀电流密度（JC）的变化规律,比较了抛光前及抛光过程中铜极化曲线的变化。定性地通过成膜的快慢及抛光过程中腐蚀电流密度的大小来说明抛光速率的高低,证明了以弱碱性溶液为介质,铁氰化钾为成膜剂,纳米γ-Al2O3为磨粒的CMP配方的可行性。     

分散剂对超细CeO2抛光液稳定性的影响

通过对超细CeO2抛光液中Zeta电位及黏度的测定,研究了溶液pH值、分散剂以及分散剂用量等因素对超细CeO2抛光液分散稳定性的影响.结果表明,固相质量分数8％的CeO2抛光液,pH值为4～5,选用非离子表面活性剂异丙醇胺作为分散稳定剂,加入质量分数为0.3％ ～0.4％时,抛光液Zeta电位较高,溶液黏度较低,抛光液...     

A comparative study: polishing characteristics and its mechanisms of three vibration modes in vibration-assisted magnetic abrasive polishing

The automatic precision polishing technique of three-dimensional complicated micro-curved surfaces of components in extremely low surface roughness and high efficiency is greatly demanded by advanced industrial fields. The existing polishing methods have great difficulty in satisfying these demands. Therefore, three modes (horizontal vibration, vertical vibration and compound vibration) of vibration-assisted magnetic abrasive polishing processes have been developed. Previous research focused on each polishing characteristic. The aims of this paper are to characterize effects of vibration of workpiece on magnetic field, polishing pressure, in-process abrasive behavior and polishing performances in three vibration modes and to describe their machining mechanism. Furthermore, a realization of efficient polishing of a 3D micro-curved surface was confirmed to be possible by the process.     

Modeling and analysis of the material removal profile for free abrasive polishing with sub-aperture pad

This paper addresses the problem of material removal in free abrasive polishing (FAP) with the sub-aperture pad both theoretically and experimentally. The effects of some polishing conditions upon the material removal are analyzed, including not only the process parameters, which refer to the normal force, angular spindle velocity and angular feed rate, but also the abrasive grain size, polishing slurry properties, topographical parameters of the sub-aperture pad, as well as tool path curvature. Based on the analysis, a model of material removal profile is proposed to facilitate more accurate polishing. First, by analyzing the contact among polishing pad, abrasive grain and workpiece surface in the micro level, the removal depth per unit length of the polishing path is derived, which is defined as the material removal index. Then, the distribution of this removal index can be obtained via modeling the pressure and relative sliding velocity in the contact region of polishing pad and workpiece. After that, the material removal profile can be calculated by integrating the material removal index along the tool path in the tool-workpiece contact region. To verify the effectiveness of the proposed model, a series of polishing experiments have been conducted. Experimental results well demonstrate that our model can accurately predict the material removal depth during the FAP.     

蓝宝石衬底CMP中氧化硅磨粒粒度分布对抛光液体系性能影响研究

目的 化学机械抛光(CMP)包含化学腐蚀和机械磨削两方面,抛光液pH、磨粒粒径和浓度等因素均会不同程度地影响其化学腐蚀和机械磨削能力,从而影响抛光效果。方法 采用30~150 nm连续粒径磨粒抛光液、120 nm均一粒径磨粒抛光液、50 nm和120 nm配制而成的混合粒径磨粒抛光液,分别对蓝宝石衬底晶圆进行循环CMP实验,研究CMP过程中抛光液体系的变化。结果 连续粒径磨粒抛光液中磨粒大规模团聚,满足高材料去除率的抛光时间仅有4 h,抛光后的晶圆表面粗糙度为0.665 nm;均一粒径磨粒抛光液中磨粒稳定,无团聚现象,抛光9 h内材料去除率较连续粒径磨粒抛光液高94.7%,能至少维持高材料去除率18 h,抛光后的晶圆表面粗糙度为0.204 nm;混合粒径磨粒抛光液初始状态下磨粒稳定性较高,抛光9 h内材料去除率较连续粒径磨粒抛光液高114.8%,之后磨粒出现小规模团聚现象,后9 h材料去除率仅为均一粒径磨粒抛光液的59.6%,18 h内材料去除率仅为均一粒径磨粒抛光液的87.7%,但抛光后的晶圆表面粗糙度为0.151 nm。结论 一定时间内追求较高的材料去除率和较好的晶圆表面粗糙度选用混合粒径磨粒抛光液,但需要长时间CMP使用均一粒径磨粒抛光液更适合,因此,在工业生产中需要根据生产要求配合使用混合粒径磨粒抛光液和均一粒径磨粒抛光液。     

Finishing effects of spiral polishing method on micro lapping surface

This study presents a spiral polishing method and a device for micro-finishing purposes. This novel finishing process has wider application than traditional processes. This offers both automation and flexibility in final machining operations for deburring, polishing, and removing recast layers, thereby producing compressive residual stresses even in difficult to reach areas. Applying of this method can obtain a fine polished surface by removing tiny fragments via a micro lapping generated by transmission of an abrasive medium through a screw rod. The effect of the removal of the tiny fragments can be achieved due to the function of micro lapping. The method is not dependent on the size of the work-piece's application area in order to carry out the ultra precise process. The application of this research can be extended to various products of precision ball-bearing lead screw. The proposed method produces products with greater precision and more efficiently than traditional processes, in terms of processing precisions and the surface quality of products. These parameters used in achieving maximum material removal rate (MRR) and the lowest surface roughness (SR) are abrasive particle size, abrasive concentration, gap, revolution speed and machining time.     

稀土CeO2增强型多孔钛的制备与性能

孔隙率对多孔钛的成骨性能影响较大,高的孔隙率更有利于骨组织的长入。但随着孔隙率的升高,其力学性能必然会急剧下降。因此,如何在保证多孔钛高孔隙率的前提下提高其力学性能,成为当前势必解决的难题。本研究采用浆料发泡法,通过在钛粉中加入不同含量的氧化铈,制备出高孔隙率的多孔钛。结果表明,多孔钛孔隙呈三维网络状,孔隙率为71.6%～73.5%,孔径主要分布在100～700μm,且孔壁上分布着微米级的微孔。当氧化铈的加入量为0.2%(质量分数,下同)时,多孔钛表现出最优的生物力学相容性,其杨氏模量为2.08GPa,抗压强度为60.19MPa。     

Study on the inner surface finishing of tubing by magnetic abrasive finishing

With the development of industry manufacturing technology, fine surface finish is in high demand in a wide spectrum of industrial applications. Presently, it is required that the parts used in manufacturing semiconductors, atomic energy parts, medical instruments and aerospace components have a very precise surface roughness. Amongst them, vacuum tubes, wave guides and sanitary tubes are difficult to polish by conventional finishing methods such as lapping, because of their shapes. The surface roughness of these tubes affects the performance of the entire system, but the finishing technology for these tubes is very scant in manufacturing fields. This project was proposed by a Shanghai Far East pharmaceutial and mechanical factory. They stated that the roughness of the inner surface must be less than 0.3 μm Ra after finishing. An internal magnetic abrasive finishing (MAF) process is proposed for producing highly finished inner surfaces of tubes used in this study. The process principle and the finishing characteristics of unbounded magnetic abrasive within internal tubing finishing are described first. MAF setup was designed for finishing three kinds of materials tubing, such as Ly12 aluminum alloy, 316L stainless steel and H62 brass. Experimental results indicated that finishing parameters such as polishing speed, magnetic abrasive supply, abrasive material, magnetic abrasive manufacturing process and grain size have critical effects on the material removal rate (MRR). How the inner surface micro shape changes course during finishing of an aluminous tube is demonstrated.     

Electrochemical planarization of patterned copper films for microelectronic applications

Electrochemical polishing (ECP) of copper (Cu) using solutions of phosphoric acid, sulfuric acid, sodium chloride, ethylene glycol, and hydroxyethylidenediphosphonic acid (HEDP), with or without organic and inorganic additives, has been investigated as an alternative to chemical mechanical polishing (CMP) for integration of low-k dielectrics in microelectronic devices. Copper anodic polarization curves in these solutions were measured. ECP of Cu bulk and thin films in these solutions was evaluated with atomic force microscopy and scanning electron microscopy. It was shown that most of the solutions studied have polarization curves with a limiting current plateau characteristic of ECP. Among them, phosphoric acid, HEDP, and phosphoric acid solutions with ethylene glycol, sodium tripolyphosphate, and Cu oxide as additives produced the best electropolished surfaces (mean roughness: R _a<10 nm) on bulk Cu. However, satisfactory ECP of electroplated patterned Cu films on silicon wafers were achieved only with an electrolyte that produced a salt film at the anode surface. Based on these experimental results, ECP mechanisms and optimal conditions for ECP of patterned Cu films plated on silicon wafers are presented. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 389–97 of the Proceedings.     

Preparation of Nano-SnO2 Abrasives and Their Application in Chemical Mechanical Polish of Ruthenium

利用固相反应法制备纳米二氧化锡磨料并研究了制备条件对平均粒径的影响.结果表明,在500 ℃/4 h条件下制得的纳米二氧化锡粉体在水中有良好的分散性和稳定性.利用自制的抛光液对高纯钌片进行化学机械抛光,与二氧化硅磨料抛光液比较,材料去除速率和表面粗糙度都降低.当抛光液中含1％(质量分数,下同)二氧化锡、1％过硫酸铵、1％酒石酸和3 mmol/L咪唑,pH=8.0,抛光压力为17.24 kPa时,材料去除速率(MRR)和表面粗糙度(Ra)分别为6.8 nm/min和4.8 nm.     

砂带磨削Q235钢工艺参数对去除率的影响

采用盘圆砂钢机对Q235钢进行了砂带磨削试验研究,对磨削后工件的材料去除率进行了分析,讨论了其最佳工艺参数组合。结果表明:在盘圆砂钢机砂带磨削Q235钢过程中,线材速度对材料去除率的影响最为显著,其次为工作台转速、砂带粒度,砂带张紧力的影响最小。仅考虑对材料去除率的影响时,最佳工艺参数组合为:砂带张紧力200 N,工作台转速500r/min,砂带粒度120#,线材速度为50m/min。此时得到的材料去除率为6.860 2g/s。     

不同粒径核壳结构聚苯乙烯(PS)-CeO2复合磨料的制备、表征及其化学机械抛光性能

以无皂乳液聚合法制备的不同粒径聚苯乙烯(Ploystrene,PS)微球为内核,以硝酸铈和六亚甲基四胺为原料,采用液相工艺制备具有核壳结构的PS-CeO2复合微球.利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、场发射扫描电镜(FESEM)、傅里叶转换红外光谱仪(FT-IR)和热重分析仪(TGA)等对样品的成分、物相结构、形貌、粒径以及团聚情况进行表征.将所制备的PS-CeO2复合微球作为磨料用于二氧化硅介质层的化学机械抛光,用原子力显微镜(AFM)观察抛光表面的微观形貌,测量表面粗糙度.结果表明:所制备的3种PS微球呈单分散规则球形,粒径分别约为120、170和240 nm;3种PS-CeO2复合微球具有核壳结构,粒径分别约为140、190和260nm,CeO2壳厚约为10 nm.随着PS-CeO2复合磨料粒径的减小,抛光表面粗糙度随之降低,经样品F1抛光后表面在10 μm× 10 μm面积范围内粗糙度的平均值（Ra）及其均方根（Rms）分别为0.372和0.470 nm.     

抛光液pH值、温度和浓度对蓝宝石抛光效率的影响

目的研究抛光液pH值、温度和浓度对化学机械抛光蓝宝石去除率的影响,以提高抛光效率。方法采用CP4单面抛光试验机对直径为50.8 mm C向蓝宝石晶元进行化学机械抛光,通过电子分析天平对蓝宝石抛光过程中的材料去除率进行了分析,采用原子力显微镜(AFM)对蓝宝石晶元抛光前后的表面形貌和粗糙度(Ra)进行了评价。结果蓝宝石在化学机械抛光过程中的材料去除率均随抛光液pH值和温度的升高呈先增大后减小趋势。当抛光原液与去离子水按1:1的体积比混合配制抛光液,KOH调节pH值为12.2,水浴加热抛光液35℃时,蓝宝石抛光的材料去除率(MRR)达到1.119μm/h,Ra为0.101 nm。结论随着pH的增大,化学作用逐渐增强,而机械作用逐渐减弱,在pH为12.2的时候能达到平衡点,此时的MRR最佳;随着温度的升高,化学作用逐渐增强,而机械作用保持不变,抛光液温度为35~40℃时,化学作用与机械作用达到平衡,MRR最佳,当温度高于40℃后,抛光液浓度明显增大,而过高的浓度会导致MRR的减小。抛光液的相关性能优化后,化学机械抛光蓝宝石的MRR较优化前提高了71.4%。     

游离和固结金刚石磨料抛光手机面板玻璃的试验研究

选取不同粒径的金刚石微粉,采用游离磨料和固结磨料两种抛光方法加工手机面板玻璃,比较其材料去除率和抛光后工件表面粗糙度。结果表明：在相同的抛光工艺参数下,磨粒粒径在游离磨料抛光中对材料去除率和抛光后表面质量作用显著,而在固结磨料抛光中作用不显著;采用金刚石固结磨料抛光垫抛光能获得表面粗糙度约为Ra1.5 nm的良好表面质量,并在抛光过程中较好地实现了自修整功能。     

乙醇对低磨料CMP过程中铜膜凹凸处去除速率选择性的影响

根据相似相容原理,在低磨料浓度CMP过程中,利用乙醇对多羟多胺螯合剂的降黏特性来提高铜膜表面凹凸处抛光速率的选择性。根据抛光液中各组分浓度对动态和静态条件下铜膜去除速率的影响获得乙醇加入量的最大值;通过螯合剂、氧化剂与乙醇对动静态条件下铜膜去除速率的相互作用关系来确定各组分的最佳浓度。最终得出当各组的体积分数为:磨料0.5%,螯合剂10%,H2O20.5%,乙醇1%时,铜膜表面拥有最大的凸处和凹处速率比。在MIT 854铜布线片上进行平坦化试验,结果表明:该抛光液能够很大程度的减小布线表面的高低差,拥有较强的平坦化能力。红外光谱检测结果表明:在CMP过程中,铜膜表面不会生成副产物乙酸乙酯。上述结果进一步证实了该抛光液的实用性。     

Effects of CeO2 doping on the structure and properties of PSN-PZN-PMS-PZT piezoelectric ceramics

Quinary system piezoelectric ceramics PSN-PZN-PMS-PZT were prepared by using a two-step method. The effects of CeO2 doping on piezoelectric and dielectric properties of the system were investigated at morphotropic phase boundary （MPB）. The results reveal that the relative dielectric constant ε33^T｜ε0, the Curie temperature To, the piezoelectric constant d33, the mechanical quality factor Qm, and the electromechanical coupling coefficient Kp are changed with the increase of CeO2 content. On the other hand, the effects of CeO2 doping on the dielectric properties of PSN-PZN-PMS-PZT piezoelectric ceramics at high electric field are consistent with the change at weak electric field. The values of dielectric constant and dielectric loss are enhanced with the increasing of electric field.     

Effects of pressure and shear stress on material removal rate in ultra-fine polishing of optical glass with magnetic compound fluid slurry

Optical glasses used in a range of industrially important optoelectronic devices must be polished to nano-level roughness for proper device operation. Polishing process with magnetic compound fluid slurry (MCF polishing) under a rotary magnetic field is an influential candidate for the method to precisely polish optical glass. MCF slurry has been successfully utilized to polish a variety of materials, ranging from soft optical polymers to hard optical glasses. MCF was developed by mixing a magnetic fluid and a magnetorheological fluid with the same base solvent, and hence includes not only μm-sized iron particles but also nm-sized magnetite particles. To elucidate the behaviour of material removal in MCF polishing, this study measured the normal and shear forces generated in the polishing zone during polishing. From these measurements, the distributions of pressure P and shear stress τ were obtained. The distribution of material removal rate (MRR) was investigated through spot polishing of borosilicate glass. The effects of three process parameters, namely magnet revolution speed, MCF carrier rotational speed and working gap, on pressure P, shear stress τ and the MRR were also investigated. The results revealed that P is higher near the centre of the interacting area (i.e. the polishing spot centre) and the point of maximum shear stress τ appears at about 5 mm from the polishing spot centre. All of P, τ and MRR are sensitive to MCF carrier rotational speed and working gap but insensitive to magnet revolution speed. Shear stress is more sensitive to these process parameters than the pressure. Cross-sectional profiles of the polishing spots exhibit a characteristic symmetric W-shape; material removals are minimal at the spot centre and maximal at approximately 8.2–10.2 mm from the spot centre depending on the process parameters. MRR is proportional to the MCF carrier rotational speed and is negatively correlated with working gap. An MRR model involving both the pressure and shear stress in MCF polishing is proposed. In the model, MRR is more dominated by shear stress than by pressure.     

负载纳米CeO2的多孔银的制备、表征及SERS研究

采用NaOH溶液腐蚀Ag/CeO2/ZnO前驱体,制备出含有纳米CeO2微粒的多孔银复合材料。随着ZnO组元被溶解,CeO2微粒均匀分散到纳米多孔银的内表面。形貌表征表明,通过调节前驱体中ZnO的含量可细化纳米多孔AgCeO2复合材料的微观结构,当ZnO加入摩尔分数为70%时,CeO2微粒尺寸为6 nm。表面拉曼增强效应(SERS)测试表明,CeO2纳米微粒的形成和分散显著增强了多孔银的SERS性能;该复合材料在可见光条件下能够降解罗丹明(R6G)并有较好的自清洁性。     

长余辉发光粒子与光催化剂在SiC晶圆化学机械抛光中的协同作用

目的 获得一种可改善单晶SiC晶圆化学机械抛光(CMP)效率的复合增效技术，实现单晶SiC晶圆高效率和低成本的加工要求，并对其增效机理进行深入研究。方法 通过抛光实验和原子力显微镜测试，探究长余辉发光粒子(LPPs)与不同光催化剂的协同作用对SiC–CMP的材料去除速率和表面粗糙度的影响。结合扫描电子显微镜(SEM)、紫外–可见漫反射光谱仪(UV–vis)、光致发光光谱仪(PL)和X射线光电子能谱仪(XPS)等仪器的测试结果，研究LPPs与光催化剂的协同增效机理。结果 与传统CMP的条件相比，在光催化条件下采用LPPs(质量分数0.5%)+TiO2(质量分数0.5%)+ H2O2(质量分数1.5%)+Al2O3(质量分数2%)的抛光液时，SiC的材料去除速率(MRR)由294 nm/h提高到605 nm/h，同时获得的晶圆表面粗糙度(Ra)为0.477 nm。然而，采用含有LPPs和ZrO2的抛光液抛光SiC时，其材料去除速率和表面粗糙度都未得到明显改善。XPS测试结果表明，LPPs与光催化剂的协同作用增强了抛光液对SiC的氧化作用。UV–vis和PL测试结果显示，LPPs与不同光催化剂协同效果的差异主要与其光学性能有关。结论 在光催化条件下，LPPs和TiO2对单晶SiC–CMP具有协同增效的作用，然而LPPs和ZrO2没有展现出协同增效的作用，即LPPs与光催化剂的协同作用可以改善SiC–CMP的性能，但是光催化剂的选择需要考虑LPPs的发光特性。