MEMS中的纳米三体磨料磨损

The key scientific problem of nanoscale three-body abrasive wear is proposed in MEMS devices including sliding/rotating parts, considering the obstacle to future MEMS devices. The experimental method and simulation technique will be built; the wear feature and mechanism of the nanoscale three-body abrasion will be discussed; the technique for reducing nanoscale three-body abrasion is investigated; the theoretical basis for solving the abrasive wear failure of MEMS is provided in this proposed project. The main research contents include: (1) the movement pattern of the nanoscale abrasive particle and contributory factor; (2) wear rule and friction law for the nanoscale three-body abrasion of the monocrystal and multicrystal silicon; (3) the phase transformation of the monocrystal and multicrystal silicon induced by the nanoscale three-body abrasion depending on the movement of the particle; (4) the effect of the phase transformation on the wear process, the movement pattern of the particle, the wear rule, the surface damage, and the material removal pattern; (5) the effect of the size and properties of the particle, the loading condition and surface state on the nanoscale abrasive wear. On this basis, the technique for reducing nanoscale three-body abrasion is investigated; the size effect of three-body abrasion is examined. The proposed project is beneficial to consummate the abrasive wear theoretic, and promote the practicability and commercialization of the MEMS devices including the sliding/rotating parts.

针对限制未来MEMS器件发展的困难，提炼和解决含滑动/旋转部件的MEMS器件磨损失效的关键科学问题：纳米三体磨料磨损。建立纳米三体磨料磨损的实验研究方法和计算机模拟技术，研究纳米三体磨料磨损的特征和机理，探索降低纳米三体磨料磨损的技术手段，为解决MEMS中三体磨料磨损所致失效的问题提供先期的理论基础。主要研究：(1)纳米磨料的运动方式及影响因素；(2)单晶/多晶硅纳米三体磨料磨损的磨损规律、摩擦法则；(3)纳米三体磨料磨损所致单晶/多晶硅的相变及其对磨料运动方式的依赖；(4)硅相变对纳米三体磨料磨损过程、磨损规律、表面损伤及材料去除方式的影响；（5）磨料几何尺寸及性能、加载条件、表面状态对纳米磨料磨损的影响规律。在此基础上探索降低纳米三体磨料磨损的方法；并对比申请人在宏观三体磨料磨损的前期工作，揭示三体磨料磨损的尺度依赖性，完善磨料磨损理论，促进含滑动/部件的MEMS器件的实用化、市场化。

微机电系统 （MEMS）以其体积小、重量轻、能耗低、智能化和集成化高等优点在航空航天、汽车工业、精密机械等领域得到了广泛的应用。三体磨料磨损是 MEMS.器件磨损失效的主要方式，直接影响着 MEMS 的寿命和可靠性。针对纳米三体磨料磨损问题，开展了四个方面的研究：(1)单晶硅的磨料磨损行为，椭球磨料的运动方式随正向载荷和磨料轴比的变化而发生滚滑转变，相比于磨料的滚动，其滑动运动方式会引起单晶硅基体更大的损伤及永久性相变；(2)二氧化硅膜磨损行为，单晶硅的整体机械性能随着二氧化硅膜厚度的变化而不同，纳米压痕过程中SiO4四面体的旋转和变形促使二氧化硅薄膜沿着压痕方向压实、减薄甚至破裂，CMP过程中二氧化硅膜越厚，去除效率越高、表面质量越好；(3)单晶铜的磨损行为，纳米压痕过程中加载速率及加载方式均会影响基体的塑性变形行为，保压过程中单晶体出现蠕变现象，残余应力的存在引起单晶铜塑性变形发生改变；（4）水润滑下单晶铜的磨料磨损行为，水膜的存在导致单晶铜在纳米压痕过程中的塑性变形增加，磨料运动过程中水膜起到了明显的减磨作用并降低了基体内部的缺陷形成。在此基础上探索降低纳米三体磨料磨损的方法，揭示了三体磨料磨损的尺度依赖性，完善了磨料磨损理论，为解决MEMS中三体磨料磨损所致失效的问题提供了先期的理论基础，促进MEMS器件的实用化、市场化。