基于变面积电容传感的大量程MEMS加速度计加工工艺研究

发布时间：2018-05-10 16:28

本文选题：MEMS + 加速度计　；参考：《华中科技大学》2015年硕士论文

【摘要】：MEMS加速度计因为体积小、重量轻、功耗小、易集成、成本低等特点在近些年得到了飞速的发展,在消费电子领域已获得了广泛应用。现阶段,以满足惯性导航、航空航天等高端领域应用需求的高精度MEMS加速度计依然是研究热点。本文旨在设计并制作基于变面积式电容传感的高精度MEMS加速度计表头,目标量程达到±15g,本底噪声小于10μg/√Hz。本文的加速度计表头采取了常见的“三明治”结构设计,通过对传统加速度计的传感模型以及变面积电容位移传感模型的理论分析,基于最终的研制目标,设计获得了加速度计包括弹簧-振子结构以及电容传感阵列的主要结构尺寸。最终设计出来的加速度计表头的机械热噪声6ng/√Hz,量程±16g。ANSYS静力学仿真分析以及模态仿真分析对本征频率及量程两个主要参数进行了验证,模拟结果符合我们的理论设计。在此基础上,针对加速度计表头的“三明治”结构,本文对各单元的功能以及单元上的功能层进行了设计,并给出了加工制作流程。流程总体上包含24个大步骤,涉及镀膜、剥离、光刻和刻蚀等多种微加工工艺。本文重点介绍了整个流程中多次使用的光刻和刻蚀工艺,并给出了经过多次优化后的最终的详细工艺加工流程及最终的加工结果。最后对我们加工出来的完整加速度计表头结合外接检测电路进行了测试,并通过对检测结果的分析对加速度计的设计进行了改进,最终实现了加速度检测功能,分辨率达到了设计指标。其中,根据测得的本征频率及Q值推知加速度计表头的等效加速度机械热噪声小于10ng/√Hz,满足我们本底噪声10μg/√Hz的设计目标;加速度检测灵敏度达到了203mV/g,接近228mV/g的设计灵敏度;对本底噪声功率谱分析表明,其在1-200Hz频段范围内的加速度分辨率为6μg,达到了设计目标。
[Abstract]:MEMS accelerometers have been developed rapidly in recent years because of their small size, light weight, low power consumption, easy integration and low cost, and have been widely used in the field of consumer electronics. At present, high precision MEMS accelerometers to meet the needs of inertial navigation, aerospace and other high-end applications are still the research hotspot. The aim of this paper is to design and fabricate a high-precision MEMS accelerometer head based on variable-area capacitive sensor. The target range is 卤15g and the background noise is less than 10 渭 g / hm2. The accelerometer head of this paper adopts the common "sandwich" structure design, through the traditional accelerometer sensor model and the variable area capacitance displacement sensing model theory analysis, based on the final development goal, The main structural dimensions of accelerometer including spring-oscillator structure and capacitive sensor array are obtained. The mechanical thermal noise (6ng/), the range 卤16g.ANSYS statics simulation analysis and the modal simulation analysis of the accelerometer head are designed to verify the intrinsic frequency and range. The simulation results are in accordance with our theoretical design. On this basis, aiming at the "sandwich" structure of the accelerometer head, the function of each unit and the function layer on the unit are designed in this paper, and the processing process is given. The process consists of 24 steps, including coating, peeling, lithography and etching. This paper mainly introduces the lithography and etching process used many times in the whole process, and gives the final detailed process flow and the final processing result after several optimization. Finally, we test the whole accelerometer head and the external detection circuit, and improve the design of the accelerometer through the analysis of the test results. Finally, the acceleration detection function is realized. The resolution reaches the design target. According to the measured intrinsic frequency and Q value, the equivalent acceleration mechanical thermal noise of the accelerometer head is less than 10ng/ Hz, which meets the design goal of our background noise of 10 渭 g / Hz. The sensitivity of acceleration detection is up to 203mV / g, which is close to the design sensitivity of 228mV/g. The analysis of background noise power spectrum shows that the acceleration resolution in 1-200Hz band is 6 渭 g, and the design goal is achieved.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH824.4

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