MEMS硅谐振式压力传感器设计

发布时间：2018-11-15 10:22

【摘要】：MEMS(微机电系统)硅谐振式压力传感器利用检测其谐振频率的改变间接测量外界环境压力,拥有体积小,精度高,抗干扰能力强等优点。另外其输出的频率信号是准数字信号,易于和后端数字电路相接。因此,MEMS谐振式压力传感器在精密控制和航空航天等需要高精度测量压力的领域有着重要作用。本文提出一种基于静电激励/电容检测的硅谐振式压力传感器,采用谐振梁和感压薄膜的复合结构作为传感器的敏感结构,对该敏感结构进行理论分析和建模,通过仿真计算,得到了敏感结构在一个大气压下的位移分布和应力分布,谐振频率随压力变化的关系曲线,以及谐振梁最大位移与激励电压的关系曲线。分析比较仿真结果,选择长方形膜作为感压薄膜,确定了谐振梁与感压薄膜的相对位置,得到敏感结构最优尺寸和激励电压的极限值,该敏感结构谐振频率约为19 kHz,灵敏度为149.37 Hz/kpa,激励电压最大不超过42.5 V。在此敏感结构基础上建立了传感器的三层硅结构模型,并进行工艺设计:采用电阻率为0.005 Ω*cm的高掺杂硅片来制作该传感器;用氮化硅来作为掩膜,湿法腐蚀和干法腐蚀相结合来制作敏感结构;硅片之间通过金硅共晶键合进行封装;通过湿法腐蚀实验得到凸角腐蚀数据,完成了掩膜版的版图绘制。
[Abstract]:MEMS (Micro-Electromechanical system) silicon resonant pressure sensor uses the change of its resonant frequency to measure the external environmental pressure indirectly, which has the advantages of small volume, high precision and strong anti-interference ability. In addition, the output frequency signal is quasi-digital signal, easy to connect with the back-end digital circuit. Therefore, MEMS resonant pressure sensor plays an important role in precision control, aerospace and other fields requiring high precision pressure measurement. In this paper, a kind of silicon resonant pressure sensor based on electrostatic excitation / capacitance detection is proposed. The compound structure of resonant beam and pressure film is used as the sensitive structure of the sensor. The theoretical analysis and modeling of the sensitive structure are carried out, and the simulation calculation is carried out. The displacement distribution and stress distribution of the sensitive structure under one atmospheric pressure, the relation curve of resonant frequency with pressure, and the relation curve between the maximum displacement of resonant beam and the excitation voltage are obtained. By analyzing and comparing the simulation results, the rectangular film is selected as the pressure sensitive film, the relative position of the resonant beam and the pressure film is determined, and the optimal size and the limit value of the excitation voltage of the sensitive structure are obtained. The resonant frequency of the sensitive structure is about 19 kHz,. The sensitivity is 149.37 Hz/kpa, and the maximum excitation voltage is no more than 42.5 V. On the basis of this sensitive structure, the three-layer silicon structure model of the sensor is established, and the process design is carried out: the sensor is fabricated by using a highly doped silicon wafer with resistivity of 0.005 惟 * cm; Silicon nitride is used as mask, wet etching and dry etching are combined to make sensitive structure, silicon wafers are encapsulated by au Si eutectic bonding, and convex corner corrosion data are obtained by wet etching experiment, and the layout of mask plate is drawn.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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