【作者】 楼飞燕；

【导师】 袁巨龙； 赵文宏；

【作者基本信息】 浙江工业大学 ， 机械电子工程， 2009， 博士

【摘要】 化学机械抛光(Chemical mechanical polishing),简称CMP,是目前在超大规模集成电路制造过程中全面平坦化应用最广泛的技术。但是CMP技术是从实践中发展起来的,其发明、发展及发展趋势、应用都是在工业界完成而不是在学术界,系统性的研究尤其是理论研究还比较缺乏。在CMP机理研究的过程中,抛光液膜厚特性的研究在CMP机理研究中占有非常重要的地位。以往所建立的抛光液膜分析模型大都以晶片与抛光垫不接触、晶片无变形、不考虑粗糙度的情况下的模型。本文根据CMP中晶片与抛光垫的三种不同接触方式,发展了两种抛光液膜的三维流体动压润滑模型和三维的部分膜流体润滑分析模型。在此基础上以抛光液膜为研究对象进行了较全面的分析和应用研究。以Reynolds方程和Reynolds出口边界条件为基础,考虑了晶片变形的影响因素,建立了抛光液膜的三维流体动压润滑分析模型。在MATLAB平台上用有限元法求解域离散,通过迭代计算得到了抛光液最小液膜厚度、液膜负荷力、晶片倾斜角、晶片变形量等性能参数。对比分析了抛光载荷、抛光转速对最小液膜厚度、晶片倾斜角的影响。抛光垫和晶片的表面粗糙度会对抛光液膜的润滑性能产生很大的影响。以三维流体动压润滑模型为基础将平均液膜厚度的几何方程联立,考虑了由粗糙度引起的压力流量因子和剪切流量因子,建立了部分膜流体润滑模型。此模型以平均Reynolds和Reynolds出口边界条件为基础,考虑晶片和抛光垫表面粗糙度的影响因素。通过数值计算得到了抛光液膜的平均液膜厚度、液膜负荷力、晶片倾斜角的性能参数。分析了抛光载荷、抛光转速、表面粗糙度、晶片变形量对平均液膜厚度、晶片倾斜角的影响。为了验证数值计算的正确性,采用了LIF技术用于CMP的可视化研究。在LIF实验装置上拍摄到抛光垫与晶片间抛光液的荧光强度图像,通过图像处理得到了不同的荧光强度值,把荧光强度值与厚度荧光强度校准曲线进行对比获得了在不同抛光转速和抛光载荷下的抛光液膜厚度。把二种模型的计算结果与实验进行了对比,结果表明三者基本一致,说明了计算模型的可行性,也为改善CMP加工工艺,提高加工效率和加工质量提供了依据。更多还原

【Abstract】 Chemical Mechanical Polishing(CMP) is a global planarization technique for large scale integrated circuit.Recently,the CMP is becoming more and more important and being used widely for high precision and global planarization.But,the CMP is developed in experience,and its creation,development,trend of development and use are finished not in academy but in industries.So,The researches systematically,especially theory research are very lack.Now, the researches for parameters of CMP technology,CMP theory model are becoming a very important subject.In the study of CMP mechanism,the research of slurry film has plays an important role in study of CMP mechanism.In the past,the most of slurry film model was built without considering the contact of wafer and pad,the deformation of wafer,roughness.In this paper,a three-dimensional hydrodynamic lubrication model and a three-dimensional partial film hydrodynamic lubrication have been developed according to three types of the contact of wafer and pad.The three-dimensional hydrodynamic lubrication model is based on the Reynolds equation and Reynolds boundary condition,and the deformation of wafer that has effects on lubrication performances of slurry film is considered.The slurry minimum film thickness,load-resistant of slurry film and tilted angle of the wafer have been obtained in solving the lubrication model.At the same time,there is an analysis on influences of load and speed of polish to minimum film thickness,tilted angle of the wafer.In the CMP,the roughness can produce great influences on lubrication performances of slurry film for the contacting of pad and wafer.The partial film lubrication mode has been presented based on three-dimensional hydrodynamic lubrication model,and considered the press flow factor and shear flow factor caused by the roughness.This model is based on the average Reynolds equation and Reynolds boundary condition,and the factors that have effects on lubrication performances of slurry film is considered,such as deformation of the wafer, roughness of the wafer and the pad are considered.The average slurry film thickness, load-resistant,tilted angle of the wafer have been obtained by solving the lubrication mode in finite element and have been analyzed influences on load,speed,roughness,deformations of the wafer.In addition,in the paper,a laser induced fluorescence technology is presented and the LIF experimental device is built for visualizing research to CMP.Using the experimental device,the slurry fluorescence intensity photos can be obtained.These fluorescence intensity photos can give the slurry film thickness information by image processing.At last,in the paper,it is found that the conclusions are similar by comparing the experiment data with numerical data.So,the models are reliable.更多还原