多场耦合作用下CeO2纳米针尖与SiO2表面微观摩擦及作用机理研究

化学机械抛光(CMP)是目前应用最广的获取原子级平面度的超光滑表面加工技术，由于缺乏对单个纳米研磨颗粒抛光机理的深入探索，限制了CMP的进一步发展。针对抛光界面的接触、摩擦及缺陷形成机理等问题，在原位研究单个CeO2纳米颗粒晶体结构、力学性质和表面氧空位形成机理的基础上，阐明铈离子的化学价态与表面氧空位的内在联系，并设计和制备出晶体结构和尺寸可控的CeO2纳米针尖。利用自制的纳米针尖模拟CMP中的纳米研磨颗粒，探索CeO2纳米针尖对SiO2表面在多场耦合(力学、温度及化学场)作用下的微观动态作用过程，考察摩擦系数与各工作参数之间的函数关系，构建摩擦界面的接触及摩擦力学模型；研究摩擦界面的微观形变过程，探索摩擦力学及材料力学行为间的物理模型关系；建立CeO2的“晶体结构”-“力学性质”-“接触与摩擦力学行为”的内在联系，为揭示CeO2研磨颗粒对SiO2的超精密抛光机理提供理论依据。

CMP is the most widely used ultra-smooth surface processing technology for getting atomic flatness. However, the further development of this technology is restricted for the lack of deeply investigation of the polishing mechanism of signal nano abrasive particle. For better understanding of the mechanisms such as the contact, friction and formation of defects, a new method based on in-situ study of the crystal structure, mechanical properties and formation mechanism of oxygen vacancy of the CeO2 nanoparticles is proposed. The homemade CeO2 nanotips with controllable crystal structure and size will be used to mimic the CeO2 abrasives in the CMP processing. Also the microcosmic dynamic between the CeO2 nanotips and SiO2 surface under multi-field coupling effect (stress field, temperature field and chemical field) will be explored. The functional relation between friction force and various parameters can be obtained. In addition, the contact and friction force models of the friction interface will be obtained respectively. Based on analyzing the microcosmic variation of friction interface, the mechanism of the deformation of SiO2 during the nano friction will be further clarified. At last, the relationship among the “crystal structure”-“mechanical properties”-“mechanical behavior of contact and friction” of CeO2 will be established which provides a theoretical basis for revealing the ultra-precision polishing mechanism of SiO2 by CeO2 grinding particles under multi-field coupling effect.