纯铅化学机械抛光中工艺参数对抛光性能的影响

为获得高质量纯铅表面，采用化学机械抛光(CMP)的方法并辅以自制抛光液，研究了胶体二氧化硅抛光颗粒的形状、粒径和浓度、加载压力、抛光头与抛光盘转向和转速、抛光液流量等工艺参数对铅片表面材料去除率和粗糙度的影响. 研究表明:小粒径异形(眉形)胶体二氧化硅抛光颗粒相较于大粒径球形颗粒更有利于铅片抛光，抛光颗粒的粒径和浓度对纯铅抛光性能的影响主要取决于铅片表面与胶体二氧化硅颗粒以及抛光垫表面丝绒的耦合作用关系. 随着加载压力、抛光头与抛光盘转向和转速、抛光液流量的改变，铅片表面和抛光垫之间驻留的层间抛光液的厚度以及状态发生改变，从而直接影响抛光液的流动性、润滑性和分散性，以及影响抛光颗粒和化学试剂与铅片表面的机械化学作用，进而影响抛光质量和材料去除率. 通过对工艺参数影响的研究和对工艺参数的优化，最终获得了表面粗糙度R_a为1.5 nm的较为理想的超光滑纯铅表面，同时材料去除率能够达到适中的380 ?/min.      

抛光垫特性及其对300mm晶圆铜化学机械抛光效果的影响研究

利用扫描电子显微镜和接触式表面形貌仪分析了IC1000/Suba-IV和IC1010两种商用抛光垫的主要特性,并通过自行研制的超低压力化学机械抛光(CMP)试验机、四探针测试仪和三维白光干涉仪等研究了这两种抛光垫对300 mm晶圆铜互连的CMP材料去除率、片内非均匀性、碟形凹陷和腐蚀的影响规律.结果表明:IC1010比IC1000的硬度低、压缩率高、粗糙度大,IC1000为网格状沟槽、沟槽较宽、分布较稀,IC1010为同心圆沟槽、沟槽较细、分布较密;相同条件下IC1010比IC1000的材料去除率大、片内非均匀性好;在相同线宽下IC1000与IC1010的腐蚀几乎一致,IC1010的碟形凹陷比IC1000的略大.     

CMP流场的数值模拟及离心力影响分析

化学机械抛光(chemical mechanical polishing,CMP)是一项融合化学分解和机械力学的工艺, 其中包含了流体动力润滑的作用.在已有润滑方程的基础上, 提出并分析了带有离心力项的润滑方程.利用Chebyshev加速超松弛技术对有离心力项的润滑方程进行求解,得到离心力对抛光液压力分布的影响. 数值模拟结果表明,压力分布与不带离心力项的润滑方程得出的明显不同;无量纲载荷和转矩随中心膜厚、转角、倾角、抛光垫旋转角速度等参数的变化趋势相同,但数值相差较大, 抛光垫旋转角速度越大差别越大.      

Modeling of dual emission laser induced fluorescence for slurry thickness measurements in chemical mechanical polishing

Dual emission laser induced fluorescence (DELIF) is a technique for measuring the instantaneous thin fluid film thickness in dynamic systems. Two fluorophores within the system produce laser induced emissions that are filtered and captured by two cameras. The ratio of the images from these cameras is used to cancel the effect of the laser beam profile on the image intensity. The resultant intensity ratio can be calibrated to a fluid film thickness. The utilization of a 2-dye system when applied to Chemical Mechanical Polishing (CMP) is complicated by the fluorescence of the polymeric polishing pad and the light scattering particles in the polishing slurry. We have developed a model of DELIF for CMP with 1-dye employing the polishing pad as the second fluorophore. While scattering particles in the slurry decrease the overall intensity of the individual images, the contrast in the image ratio increases. Using the 1-dye DELIF system to measure thin slurry films, our model results indicate that a cubic calibration may be needed. However, experimental results suggest a linear calibration is achieved for slurry films between 0 and 133???m thick with scattering coefficients as high as 8.66?mm^?1 at a wavelength equal to 410?nm.     

An extension of the linear stability analysis for the prediction of multiple necking during dynamic extension of round bar

Linear stability analysis has been widely used in order to describe the evolution of the dominant necking pattern in different configurations. Effects of hardening, strain rate and temperature sensitivity, and effects of configuration geometry and loading, have been established by this mean. However, experimental and numerical observations have demonstrated that a whole distribution of spacing between necks is obtained instead of a unique dominant pattern. In this work, an extension of the classical linear stability analysis applied to the dynamic extension of a round bar case has been developed to take into account the contribution of all perturbation modes on the preliminary evolution of pre-necks. This approach, corresponding physically to the case of thin ring expansion, is able to determine a distribution of pre-neck spacing. This distribution, starting from the initial perturbation pattern, evolves with time so that it is finally centered around a dominant distance determined by the linear stability approach.     

纳米磨料对硅晶片的超精密抛光研究

采用均相沉淀法制备了纳米CeO2和纳米Al2O3超细粉体,将所制备的超细粉体配制成抛光液并用于硅晶片化学机械抛光,考察了纳米磨料对硅晶片抛光效果及抛光机理的影响.结果表明,纳米CeO2磨料的抛光效果优于纳米Al2O3磨料,采用纳米CeO2磨料抛光硅晶片时可以得到在1μm×1μm范围内微观表面粗糙度Ra为0.089nm的超光滑表面,且表面微观起伏较小.     

钛基片的化学机械抛光技术研究

采用化学机械抛光（CMP）方法对钛基片进行纳米级平坦化处理,通过系列抛光试验优化抛光液组成和抛光工艺条件后,得到AFM-Ra为0.159 nm的纳米级抛光表面和156.5 nm/min的抛光速率。抛光液的电化学分析结果表明：二氧化硅颗粒和乳酸在钛表面有不同程度的吸附缓蚀作用,氨水和F-的络合、扩散作用能破坏缓蚀膜层,两者的中间平衡状态才能得到最佳抛光效果。抛光后钛表层XPS测试结果显示钛表层经过化学氧化形成疏松氧化层后,再通过磨粒和抛光垫的机械作用去除。     

Ce0.8Zr0.2O2固溶体磨料对ZF7光学玻璃抛光性能的改善

采用改进的湿固相机械化学反应法制备出超细锆掺杂氧化铈磨料Ce1-xZrxO2(x=0,0.2),运用X射线衍射(XRD)、透射电镜(TEM)等手段表征其物相类型、外观形貌、比表面积、粒度、表面电位等物理性质,通过测定抛光速率和观察表面的微观形貌考察它们对ZF7光学玻璃的抛光性能影响.结果表明,Ce0.8Zr0.2O2固溶体磨料对ZF7光学玻璃抛光性能比纯CeO2磨料有明显的提高,抛光速率达到463 nm/min,5.0 μm×5.0 μm的范围内微观表面粗糙度Rα值达到1.054 nm,而纯CeO2磨料的抛光速率只有292 nm/min,Rα值却增大到1.441 nm.Ce0.8Zr0.2O2固溶体的抛光速率的明显增大和表面粗糙度Rα的下降主要与其负表面电位的增大和颗粒尺寸、粒度的减小密切相关.     

盘式制动器摩擦界面接触压力分布研究

在考虑具有可变效应的移动热源影响、制动盘与片的弹性影响以及界面摩擦热流影响等的耦合作用下,建立了一个三维瞬态盘式制动器热-结构耦合模型,利用大型有限元软件ANSYS的非线性多场耦合分析方法,分别数值模拟了不同状态下的制动器摩擦接触界面上的压力场分布情况.发现制动接触压力并非均匀分布,而是与制动盘和片的变形、摩擦力以及摩擦热-结构耦合有关.     

考虑对流效应和磁场的CMP模型及其数值模拟

推导了具有对流效应的化学机械抛光(chemical mechanical polishing,CMP)润滑模型,研究各参数对压力场分布的影响.在此模型基础上,研究了磁流体抛光液在外界磁场作用下的润滑模型,以及外磁场对抛光过程中压力场分布的影响. 数值结果表明,具有对流效应的润滑模型的压力分布与已有经验结果更一致,能更为有效地解释CMP过程中的负压现象; 进一步通过外界磁场的作用, 可以有效地改变磁流体CMP的压力分布,这为实现对晶片的全局抛光提供了一种可供参考的新途径.