【作者】 李源；

【导师】 胡小唐；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2007， 博士

【摘要】 针对微小结构和器件对大范围、高精度的坐标测量方法和装置的需求,本论文研究了一种基于压阻检测原理的MEMS三维微触觉式测头,并基于纳米测量机(NMM)构建了相应的几何量测量系统。论文完成了以下主要工作:1.设计了一种采用由测杆和悬挂系统组成的压阻式微触觉测头,并基于结构矩阵分析和材料力学原理,创建了测头的力学分析模型。计算了测头的整体刚度、敏感梁的应力分布、测头灵敏度、变形范围和线性范围等参数,建立了测端位移与压阻敏感单元应力变化之间的对应关系;研究了测量过程中测头和样品之间静态力、动态力等受测头结构参数和坐标测量机运动参数的影响机理;同时建立了测头压阻敏感单元的三维检测模型,分析了敏感梁的应力分布状况,确定了压阻单元的敏感方向、类型、压阻数目、网络排布方式和结构尺寸。2.建立了测头有限元仿真模型并进行测头结构的优化。模拟计算了测头的应力分布、刚度、机械强度、疲劳极限、共振频率等性能参数,选择合适的测头悬挂系统拓扑结构和测杆结构,并在工艺实现的基础上,创新性地提出了微尺度下的测杆与中心连接体的定位和对准方法和装置,实现了测头各单元之间的精密装配;基于测头力学模型确定结构参数的大概范围,根据测头的梁、中心连接体、测杆等结构参数对性能影响程度,选择了测头各单元最优化的结构形式和参数;基于理论分析的结论,与优化参数的仿真数据进行了的比对和验证。3.研究了微触觉测头的工艺加工技术。设计了测头悬挂系统的MEMS版图,研究了加工过程中有关压阻、凸角补偿等关键工艺,制定工艺流程,并与北大微电子所合作加工了测头悬挂系统;基于超精密加工技术,实现了测杆及其顶端触觉小球的制造,并根据NMM对测头工作空间的要求,研究测头的封装方式和固定方法,实现和外围处理电路的电连接。4.开展了微触觉测头的性能测试。首次创建了基于NMM的微触觉测头的性能测试系统,研究了压阻检测电桥输出微弱电信号的滤波、放大等方法,设计了压阻信号采集调理电路中及相应的软件功能模块;开展了对测头的线性、灵敏度、迟滞、和耦合特性的测试;利用精密压电陶瓷驱动器,构建测头低频振动测试平台,考察和测量了测头对低频信号的响应情况,分析了测头性能的稳定性。5.结合NMM平台,实现对被测结构的三维高精度几何量测量。通过给NMM引入微测头输出的反馈信号,实现NMM的运动控制功能;利用NMM的计量学功能,实现了对被测物的高精度几何量测量,通过对被测物的线扫描分析和表面形貌扫描,研究了测头的扫描测量的性能;最后,分析了测量过程中测头自重、磁性、振动等因素对测量过程造成的误差影响。更多还原

【Abstract】 In measurement field of micro structure and device’s 3D dimension, position, and topography, the coordinate measurement method and instrument with large range and high precision play important roles. As the probe of Nanomeasuring machine (NMM), a MEMS 3D micro tactile probe based on piezo-resistance effect is developed. Based on the NMM, probe performance test and measuring system is constructed. The follow is the main contents of this paper:1. Based on structure matrix analysis and material mechanical theory, a mechanical module of probe is presented. The stress distribution of beam, stiffness, sensitivity, and linearity of probe are calculated. Relationship between displacement of probe tip and stress distribution of piezo-resistors is set up. Influence mechanism of the static force and dynamic force between probe and sample during the measurement, induced by probe structure parameters and coordinate measurement machine parameters is studied. Meanwhile, 3D analytical module of piezo resistors is presented. Stress distribution of beam is analyzed. The direction, type, number, arrangement and dimension of piezo resistors are designed.2. Through the ANSYS Finite Element Method, the stress distribution, stiffness, and resonance of probe are simulated. The suspending topological structure and stylus are designed. For the consideration for MEMS technics implement, methods and equipments about position and alignment between stylus and intermediate are presented, and precision assembly with self-alignment and self-position is achieved. Compared with the probe performance of standard parameters, according to the influence degree of structure parameters of beam, intermediate body, and stylus, optimum structure and parameters are chosen. Simulated data of optimum structure are compared and validated with the conclusion of theoretical anlysis.3. The MEMS layout of suspending structure is designed. Key technics, such as piezoresistors, convex compensation of KOH are studied. Cooperated with Department of Microelectronics of Beijing University, the suspending structure is fabricated. Using the high precision fabrication technique, the tip and stylus are machined. According to requirement of workspace of NMM,package and fix house of probe are designed to connect to signal conditioning circuit.4. Combined with NMM positioning platform, the performance test system of micro tactile probe is constructed. The filter and amplification theory and method of output weak signal by Wheatstone bridge of piezoresistors are studied. Signal conditioning circuit and corresponding functional modules are designed. The linearity, sensitivity, resolution, cross-talk and hysteresis are tested and analyzed. A low frequency vibration test system of probe using the precision PZT is constructed. The response to low frequency vibration signal is observed, and stability of performance is analyzed.5. Through feedbacking output signal of probe into NMM, movement control of NMM is achieved. Using the metrological function of NMM, dimension measurement with high precision is realized. By analysis of line scan and topographical scan, the scanning performance is studied. Finally, the errors induced by gravity of stylus, magnetic force, shift of stylus and vibration of environment are discussed.更多还原