化学机械抛光中抛光液流动特性研究
发布时间：2018-11-17 15:43
【摘要】：化学机械抛光作为一种具有独特优势的加工工艺手段,在微电子领域以及光学加工领域已经有着十分广泛的应用。化学机械抛光中,抛光液作为提供化学反应物质,排除加工碎屑的加工介质,在工艺中占有重要地位。抛光液的流动过程能够将抛光所需的化学物质以及磨料输送至抛光垫表面、带走摩擦生成的热量以及加工产物,维持稳定的抛光加工环境,同时,抛光液在流动中能够在工件与抛光垫之间建立具有承载力的润滑薄膜,改善工件与抛光垫的接触状态。为了能够弄清化学机械抛光加工中抛光液流动规律,研究抛光垫表面形貌对抛光液流动的影响,优化抛光垫表面形貌来控制抛光液的流动,本文开展了以下研究:1.平整的无沟槽抛光垫表面抛光液流动状态分析。使用流体力学方程推导抛光液在无粘性假设下的流动状态,使用有限元法对抛光液流动行为进行的仿真结果显示,抛光液由于由内而外的加速运动趋势以及增大的湿周长度,液面高度呈现明显下降,流动均匀性差。使用粒子图像测速实验验证了仿真结果。2.结合多相流模型的有限元仿真和粒子图像测速实验,探索了具有沟槽的抛光垫表面抛光液的流动特性。抛光液在抛光垫沟槽中流动,受到明显的阻挡作用,抛光液流动的沿程能量损失显著,相比于平整无沟槽抛光垫表面的情况,具有沟槽的抛光垫表面流动具有更高的液膜厚度,不易导致碎屑的沉降,有利于高效排出碎屑;抛光液从内而外的径向流动速度变动也得到了一定程度的改善。对多种不同沟槽网格形状的抛光垫中流动状态进行了比较和讨论,结果显示网格形状为正六边形时,抛光液流动的均匀性最佳。3.抛光垫表面沟槽优化设计。在对抛光液流动沿程能量损失的理论下,对抛光垫表面沟槽进行了优化设计,优化涉及沟槽宽深比、沟槽尺寸以及沟槽沿抛光垫表面的分布走向。使用有限元仿真手段对优化的沟槽中抛光液流动状态进行了分析,结果显示其流动径向速度均匀,且具有一致的液面高度,实验结果也显示沟槽中径向流速均匀一致,达到了预期的优化效果。
[Abstract]:Chemical mechanical polishing (CMA) has been widely used in the field of microelectronics and optical processing as a kind of processing technology with unique advantages. Polishing fluid plays an important role in the process of chemical mechanical polishing. The flow process of the polishing liquid can transport the chemicals and abrasives needed for polishing to the surface of the polishing pad, take away the heat generated by friction and the processing products, and maintain a stable polishing environment, at the same time, The lubricating film with bearing capacity can be established between the workpiece and the polishing pad during the flow of the polishing liquid, and the contact state between the workpiece and the polishing pad can be improved. In order to make clear the flow rule of polishing fluid in chemical mechanical polishing process, to study the effect of polishing pad surface morphology on polishing liquid flow, and to optimize the surface morphology of polishing pad to control the flow of polishing liquid, the following researches have been carried out in this paper: 1. Surface polishing fluid flow analysis of smooth grooveless polishing pad. The fluid dynamics equation is used to deduce the flow state of the polishing fluid under the assumption of non-viscosity. The simulation results of the flow behavior of the polishing liquid by using the finite element method show that the polishing fluid is due to the tendency of acceleration from inside to outside and the increase of the wet cycle length. The height of liquid level decreased obviously and the flow uniformity was poor. The experimental results of particle image velocimetry are used to verify the simulation results. 2. Based on the finite element simulation of multiphase flow model and particle image velocimetry experiment, the flow characteristics of polishing fluid on the surface of polishing pad with grooves are investigated. The flow of polishing fluid in the grooves of the polishing pad is obviously blocked, and the energy loss along the course of the flow of the polishing fluid is significant. Compared with the case of leveling the surface of the polishing pad without grooves, the surface flow of the polishing pad with grooves has a higher liquid film thickness. It is not easy to cause detritus sedimentation, which is beneficial to the removal of detritus efficiently. The variation of radial velocity of polishing fluid from inside to out has also been improved to some extent. The flow state of polishing pad with different groove mesh shapes is compared and discussed. The results show that the uniform flow of polishing fluid is the best when the mesh shape is hexagonal. 3. Surface groove optimization design of polishing pad. Based on the theory of energy loss along the polishing fluid flow, the groove on the surface of the polishing pad is optimized, which involves the ratio of width to depth, the size of the groove and the distribution of the groove along the surface of the polishing pad. The flow state of polished liquid in the optimized grooves is analyzed by finite element simulation. The results show that the radial velocity is uniform and the liquid level is uniform. The experimental results also show that the radial velocity in the grooves is uniform and consistent. The desired optimization effect is achieved.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG175
[Abstract]:Chemical mechanical polishing (CMA) has been widely used in the field of microelectronics and optical processing as a kind of processing technology with unique advantages. Polishing fluid plays an important role in the process of chemical mechanical polishing. The flow process of the polishing liquid can transport the chemicals and abrasives needed for polishing to the surface of the polishing pad, take away the heat generated by friction and the processing products, and maintain a stable polishing environment, at the same time, The lubricating film with bearing capacity can be established between the workpiece and the polishing pad during the flow of the polishing liquid, and the contact state between the workpiece and the polishing pad can be improved. In order to make clear the flow rule of polishing fluid in chemical mechanical polishing process, to study the effect of polishing pad surface morphology on polishing liquid flow, and to optimize the surface morphology of polishing pad to control the flow of polishing liquid, the following researches have been carried out in this paper: 1. Surface polishing fluid flow analysis of smooth grooveless polishing pad. The fluid dynamics equation is used to deduce the flow state of the polishing fluid under the assumption of non-viscosity. The simulation results of the flow behavior of the polishing liquid by using the finite element method show that the polishing fluid is due to the tendency of acceleration from inside to outside and the increase of the wet cycle length. The height of liquid level decreased obviously and the flow uniformity was poor. The experimental results of particle image velocimetry are used to verify the simulation results. 2. Based on the finite element simulation of multiphase flow model and particle image velocimetry experiment, the flow characteristics of polishing fluid on the surface of polishing pad with grooves are investigated. The flow of polishing fluid in the grooves of the polishing pad is obviously blocked, and the energy loss along the course of the flow of the polishing fluid is significant. Compared with the case of leveling the surface of the polishing pad without grooves, the surface flow of the polishing pad with grooves has a higher liquid film thickness. It is not easy to cause detritus sedimentation, which is beneficial to the removal of detritus efficiently. The variation of radial velocity of polishing fluid from inside to out has also been improved to some extent. The flow state of polishing pad with different groove mesh shapes is compared and discussed. The results show that the uniform flow of polishing fluid is the best when the mesh shape is hexagonal. 3. Surface groove optimization design of polishing pad. Based on the theory of energy loss along the polishing fluid flow, the groove on the surface of the polishing pad is optimized, which involves the ratio of width to depth, the size of the groove and the distribution of the groove along the surface of the polishing pad. The flow state of polished liquid in the optimized grooves is analyzed by finite element simulation. The results show that the radial velocity is uniform and the liquid level is uniform. The experimental results also show that the radial velocity in the grooves is uniform and consistent. The desired optimization effect is achieved.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG175
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