【作者】 郑晓虎；

【导师】 朱荻；

【作者基本信息】 南京航空航天大学 ， 机械工程， 2007， 博士

【摘要】 随着微电子技术和微加工技术的发展,越来越多的微型传感器、执行器走进了实际应用。根据工作原理,微器件可分为静电、压电、热、电磁等类型,其敏感、致动元件的性能差别很大。电磁驱动的微器件具有在较低的电压下能获得较大位移和驱动力的特点,易于实用。这一类器件所面临的共同问题是微型线圈与磁性元件的制作。本文以涡流传感器为对象,研究了基于平面线圈实现的电磁型微传感/执行器的关键技术,制作出直径为2.4mm、厚度为1.6mm的涡流传感器原型样机,能够在高温、窄缝条件下实现间隙、缺陷的检测。为基于微平面线圈的微器件工程化奠定基础。本文从以下几个方面进行研究。首先,根据电磁场的基本理论,研究了微平面线圈的电磁场分布规律、电感特性及磁膜对电铸平面线圈特性的影响。建立了传感器的数学模型,给出电涡流传感器的基本性能。研究了平面线圈的光刻工艺,以正交实验方法为基础,结合模糊神经网络技术,建立光刻图形质量与工艺参数之间的预测模型,模型为5层结构采用BP算法。提出并研究了基于图形特征的显影工艺。得出不锈钢基底上采用SU-8胶实现的大面积微结构的最优工艺,制作出微平面线圈胶模。深入研究了微结构电铸,在分析微细电铸的电场与流场特性的基础上,推导出微细电铸的传质模型,讨论了铸层厚度的不均匀现象及搅拌方式、电流密度对电铸质量的影响,分析了超声在微细电铸过程中的作用机理,得出最佳超声功率与电流密度,制造出线宽70μm、间隙30μm的平面线圈。详细讨论了传感器铁芯的Ni-Fe合金电铸工艺,深入分析铸层铁含量与电解液成分、温度、电流密度等参数的变化规律;同时研究了铸层合金的组织形貌、显微硬度、耐蚀性等机械性能;详细讨论了电铸层饱和磁化强度、矫顽力、剩磁等电磁特性,实验表明:电铸Ni-Fe合金电磁性能优于坡莫合金,实现了传感器铁心的制造。最后,研制了两层线圈与磁芯相叠加结构的电涡流传感器原型样机,开发出数字检测系统及微运动平台,对样机进行了性能试验。传感器的最大灵敏度为:0.55 mv/μm,精度:20μm。更多还原

【Abstract】 With the development of microelectronic and micromachining techniques, more and more micro sensors and actuators have been reported for using in various application. According to the different sensing-actuation mechanisms, micro devices can be classified into serval categories: electrostatic, piezoelectric, thermal, and magnetic. The properties of various types MEMS devices diverse greatly, which has been a hotspot in engineering application.Larger displacement and force could be achieved through magnetical micro devices than others. A key issue of this type device is the fabrication of micro coil and magnetic component. Some key technologies such as the fabrication, assemble and test of micro magnetic sensor and actuator using planar coil were studied in the paper, with the micro magnetic relay and micro eddy current sensor as targets. A prototype eddy current sensor with 2.4 mm diameter and 1.6 mm thickness was fabricated and studied. The whole work play an important role in the application of magnetic MEMS devices based on the planar coil. Several aspect of works, as follows, were carried out in this paper.Firstly, the electromagnetic field distribution and inductance attribute of micro planar coil were investigated based on the fundmental theory. Combined with Finite element method (FEM), an analytical model of an eddy current sensor for noncontact distance measurement was presented, which laid the foundations for future experiment.With SU-8 photoresist, the large area micro pattern on the metal substrate fabricated by using photolithographic technology was studied in this paper. In order to obtain the suitable parameters of the various thickness photoresist, an artificial neural network (ANN) with 5 layers was built in research. The ANN was trained based on orthogoality experiment using back propagation algorithm. Compared to the experiment results, the prediction error was less than 2.0%, which proved that the ANN was effective. Definitions of image feature were put forward. Based on these concepts, develop process was analysised in detail, the optimal process of SU-8 based on the stainless substrate was given.The characteristics of the microelectroforming process was analysed systematically through Finite element analysis (FEA) of electric field and flow field of the micro deposit area. The effects of the main parameters, current density and stiring style, on the deposit quality (uneven thickness distribution, etc.) were discussed in detail. The mechanism and influencing on ultrasonic stiring in the microelectroforming was explained, based on the studies, the optimal ultrasonic power and current density was introduced. The results showed that the mass transfer was the control factors of deposit quality. A planar coil with 70μm line width,30μm line distance was fabricated according to the above research.This paper was focused on the composition controlling, coating microstructure and electromagnetic character of Ni-Fe deposit for MEMS device. The relation between the deposit composition and the main parameters, such as current density, temperature, electrolyte concentration, were investigated in deep. The results indicated that the Ni-Fe deposit was bright and compact. The resistivity of deposit was about 30μ?·cm, when the Fe(wt.%) ranged from 10% to 50% in the deposit. Electrodeposited Ni-Fe has a strong paramagnetism effect and the coercivity showed a monotonic decrease with increasing Fe content in deposit, the saturation magnetization was only 10% of that of the IJ85 permalloy, which proven that the electroformed Ni-Fe alloy had good electromagnetic property and could be used in MEMS actuator fabrication.Finally, a prototype of eddy current sensor was fabricated with UV-LIGA technology and the electroforming magnetic core process. The device consists of two planar coil (driver coil and pickup coil) stacked on the magnetic core. The character of the device was tested with micro motion platform and data acquisition system developed independently. The optimal sensitivity was 0.55 mv/μm and resolute was 20μm. The whoil work was a beneficial trial to the practice of magnetic MEMS devices based on the planar coil.更多还原