大面积匀强磁场励磁的蓝宝石晶片高效磁流变化学平整加工

This study proposes a high-efficiency magnetorheological chemical planarization (MRCP)method under large uniform magnetic field excitation to perform high-efficiency, damage-free and ultra-smooth machining for sapphire wafer and overcome the existing problems of low efficiency and surface and sub-surface damage in chemical mechanical polishing (CMP) process. The MRCP method regulates stiffening of magnetorheological chemical polishing fluid, which subsequently functions as a large, uniform and stable polishing tool. A novel magnetorheological chemical polishing fluid (MRCPF) is also developed, consisting of nano-order abrasives and catalyzer. Effects of excitation mode on polishing tool and polishing performance are studied. Effects of the process parameters and polishing fluid component on polishing performance （material removal rate, surface roughness, flatness, surface and sub surface damage in sapphire substrate planarization process are examined. The magnetic rheological properties of MRCPF under large uniform magnetic field excitation, material removal mechanism, damage control mechanism are also revealed with respect to the fundamentals of fluid mechanics, magnetics, interface chemistry, wear chemistry friction, through which new high performance process can be developed to achieve sub-nanometer surface roughness. This study lays the technical and theoretical foundations for high-efficiency, damage-free and ultra-smooth machining of sapphire wafer.

针对蓝宝石晶片高效率、无损伤、超光滑的加工要求，以及现有化学机械抛光（CMP）存在抛光损伤及低效率的问题，提出采用大面积匀强磁场励磁，控制磁流变化学研抛液硬化成大面积的研抛工具，形成高效磁流变化学平整加工的新方法，并研究包含高性能纳米复合磨料及催化剂的新型磁流变化学研抛液，从而高效率地得到无损伤、超光滑表面。通过综合研究励磁方式对研抛工具及研抛性能的影响规律、加工工艺参数及磁流变化学抛光液组分对蓝宝石晶片平整加工性能（材料去除率、表面粗糙度、平整度、表面及亚表面损伤）的影响规律，以流体力学、磁力学、界面化学、摩擦化学等原理为基础，揭示磁流变化学抛光液在大面积匀强磁场作用下的流变学特性、磁流变化学加工的材料去除机理、损伤控制机理，获得亚纳米级、无损伤表面平整加工的有效方法和途径。为实现蓝宝石晶片高效率、无损伤、超光滑的大面积平整加工提供技术和理论支持。

针对蓝宝石晶片高效率、无损伤、超光滑的加工要求，以及现有化学机械抛光（CMP）存在抛光损伤及低效率的问题，提出采用大面积匀强磁场励磁，控制磁流变化学研抛液硬化成大面积的研抛工具，形成高效磁流变化学平整加工的新方法，并研究包含高性能纳米复合磨料及催化剂的新型磁流变化学研抛液，从而高效率地得到无损伤、超光滑表面。通过综合研究励磁方式对研抛工具及研抛性能的影响规律、加工工艺参数及磁流变化学抛光液组分对蓝宝石晶片平整加工性能（材料去除率、表面粗糙度、平整度、表面及亚表面损伤）的影响规律，以流体力学、磁力学、界面化学、摩擦化学等原理为基础，揭示磁流变化学抛光液在大面积匀强磁场作用下的流变学特性、磁流变化学加工的材料去除机理、损伤控制机理，获得亚纳米级、无损伤表面平整加工的有效方法和途径。为实现蓝宝石晶片高效率、无损伤、超光滑的大面积平整加工提供技术和理论支持。