基于介电泳效应的抛光新方法研究

A novel polishing method that is based on dielectrophoretic(DEP) effect is proposed to tackle problems often associated with traditional polishing process, such as short dwell time of abrasive within polishing zone, low utilization of abrasive, low machining efficiency, and high non-polishing consumption of abrasive. The novel method employes non-uniform electric field to polarize polishing slurry and abrasive within the polishing zone. Slurry and abrasive with surface induced electric charge move toward the electrode under the DEP force of non-uniform electric field and adsorb on a polishing pad near the electrode. It suppresses the thrown-out effect of slurry and abrasive due to centrifugal force during polishing; extends the dwell time of slurry and abrasive within the polishing zone; enhances the material removal effect of polishing media; and improves polishing efficiency. It also reduces non-polishing slurry and abrasive consumption due to thrown-out effect and reduces manufacturing cost. This project will unveil the mechanism of DEP effect in polishing; analyze the characteristics of kinematics and dynamics of slurry and abrasive under non-uniform electric field; study work piece material removal mechanism during machining process; explore key factors and methods for quantitatively controlling DEP effect; establish an experimental machining platform; optimize machining techniques and processing parameters; and develop a novel polishing method with high efficiency and low cost. This project has important scientic significance and engineering application value in enriching machining technology with ultra-precision abrasive.

针对传统抛光过程中，加工区域抛光液驻留时间短、利用率低，导致加工效率低、抛光液无效损耗高等问题，提出了一种基于基于介电泳效应的抛光新方法：利用非均匀电场使加工区域中的抛光液及其中的磨粒发生极化，表面产生感应电荷的抛光液和磨粒受到非均匀电场的介电泳力作用，向电场的极板移动，并被吸咐在极板附近的抛光垫上，抑制了离心力对抛光液及磨粒甩出作用，延长抛光液和磨粒在加工区域的驻留时间，增强了抛光介质对工件的去除作用，提高了抛光效率。同时，减少了抛光液和磨粒甩出造成的无效损耗，降低了生产成本。本项目研究揭示介抛光过程中介电泳效应的作用机理，分析非均匀电场条件下抛光液和磨粒的运动学和力学特性，研究加工过程中的工件材料去除机理，探索介电泳效应定量控制的关键因素和方法，构建加工实验平台，优化加工方式及工艺参数，发展了一种高效、低成本的抛光新方法，对丰富超精密磨粒加工技术具有重要的科学意义和工程应用价值。

针对传统抛光过程中，加工区域抛光液驻留时间短、利用率低，导致加工效率低、抛光液无效损耗高等问题，提出了一种基于介电泳效应的抛光新方法：利用非均匀电场使加工区域中的抛光液及其中的磨粒发生极化，表面产生感应电荷的抛光液和磨粒受到非均匀电场的介电泳力作用，向电场的极板移动，抑制了离心力对抛光液及磨粒甩出作用，增强了抛光介质对工件的去除作用，提高了抛光效率。减少了抛光液和磨粒甩出造成的无效损耗，降低了生产成本。.项目完成工作：（1）介电泳效应抛光方法原理研究，以静电场基本理论为基础，推导出了非均匀电场中磨粒的介电泳力和运动速度表达式；利用COMSOL软件对不同电极形状产生的非均匀电场场强分布进行仿真，获得加工区域电场强度平方的梯度分布，推导加工区域磨粒所受的介电泳力大小；理论分析和实验观测了介电泳效应的磨粒和抛光液运动方向；（2）根据Preston方程建立了介电泳抛光的工件材料去除模型，分析了介电泳抛光方法的主要影响因素；（3）开发了介电泳效应抛光的专用电源，搭建介电泳效应抛光实验台；（4）以3英寸硅片为加工对象，开展介电泳效应抛光实验。不同电极形状非均匀电场的介电泳效应抛光实验结果表明：直径60mm圆形电极形状产生非均匀电场，其介电泳效应抛光最好；介电泳效应抛光和传统抛光对比实验结果表明：介电泳效应抛光后硅片的表面质量和抛光效率优于传统抛光方法后的硅片；对极间电压（场强）、电源频率、加工载荷和抛光盘转速四个工艺参数影响介电泳效应抛光实验结果表明：电源频率40Hz，极板间电压1500V，加工载荷4000g，抛光盘转速60r/min，硅片的抛光效率和质量最好。.本研究实现了高精度、高效、低成本的超精密平面抛光。项目成果获2016年度浙江省科学技术进步奖一等奖。申请发明专利13项（已授权发明专利3项），授权实用新型专利10项；发表学术论文7篇，其中：SCI论文1篇，已录用EI论文2篇；协助承办会议6次；培养博士生2名，硕士生4名（已毕业2名）。