【作者】 吴澄；

【导师】 陈迪；

【作者基本信息】 上海交通大学 ， 微电子学与固体电子学， 2011， 硕士

【摘要】 生物电势的测量记录在医学应用以及学术研究中发挥着重要的作用,是不可缺少的一种关键手段,其中脑电图(EEG)更是在研究大脑功能与疾病方面起着极其重要的作用。传统测量EEG方法是采用湿电极,使用方法较为复杂且受所处环境的限制较大,而新型的干电极使用起来更为简单且可便携化,符合现代医疗保健个人化的社会需求。MEMS技术是近年来随着硅微加工技术发展起来的一种微加工技术,通过光刻等技术,可以在微米甚至纳米尺度上制备元器件。近几年来,在MEMS领域中出现了柔性MEMS和Bio-MEMS技术。柔性MEMS技术在柔性基底上加工出微米尺度的器件,这样制备的器件具有能经受冲击、能够折叠弯曲等优点;而Bio-MEMS技术利用MEMS技术制造体外分析诊断器件和体内植入器件。本文的研究内容包括:基于微机电系统(MEMS)工艺以及EEG信号采集要求设计了多种微针干电极,包括立体电极、聚酰亚胺衬底平面电极和全金属平面电极三种。其中立体电极阵列为10×10,每根微针的直径分别为50μm、60μm、80μm;聚酰亚胺衬底平面电极分为两批,第一批微针尺寸为250μm(l)×50μm(w)、300μm(l)×60μm(w)与350μm(l)×80μm(w),高度均为40μm,第二批为300μm(l)×150μm(w)与500μm(l)×200μm(w),高度均为60μm;全金属平面电极分为直针和斜针,直针尺寸与第二批聚酰亚胺平面电极相同,斜针还包括底座,与电极夹角60°,斜针尺寸350μm(l)×150μm(w),高度为60μm,底座边长为500μm。第二,设计了微电极阵列的MEMS加工工艺,利用溅射、刻蚀、光刻、电镀等工艺实现了微电极阵列的制备。实现了不同的工艺流程,并进行工艺后分析。在溶液浓度0.9%的生理盐水中测试了平面电极,在0.1 Hz到1000 Hz之间的阻抗总体情况都达到了100 k?～100 ?。第三,进行了人体实验,将平面电极与传统湿电极的效果进行了比较,也进行了不同平面电极之间的比较。证实每种电极都能采集到脑电信号,其中第二批聚酰亚胺衬底平面电极和全金属平面电极(直针)采集到的信号较好,尤以6片至10片组装的效果最佳。更多还原

【Abstract】 Biopotential recordings are indispensable and vital tools for both medical and research use, especially in the form of electroencephalogram (EEG), which plays an important role in the study of brain function and diseases. Generally, a wet electrode is used in EEG recording and its use is quite complicated and limited by the environment. However, novel dry electrode is more convenient to use and can be portable, which is in line with modern personalized health care needs of the society.MEMS technology is a kind of micro manufacture technology which develops along with silicon micro manufacture technology. By fabrication process such as photolithography, we can manufacture device in micro or nano dimension. In recent years, flexible MEMS and Bio-MEMS have emerged. Based on flexible substrate, device in micrometer dimension can be fabricated by MEMS technology, and these devices can bear impact and can be curved. In vitro diagnostic device and vivo implanted device, Bio-MEMS technology can provide edges as well.Based on MEMS technology and the requirement of EEG recording, we first design the configuration of three various types of dry electrodes with microneedles, including 3D electrode, plane electrode based on Polyimide (PI) substrate and plane metal electrode. The fabricated 3D electrode has an array of 10×10 grid, with the diameters of microneedles being 50μm, 60μm and 80μm. There are two groups of plane electrodes based on PI substrate, the first of which has microneedle sizes of 250μm(l)×50μm(w), 300μm(l)×60μm(w) and 350μm(l)×80μm(w), with height of 40μm, the second of which has microneedle sizes of 300μm(l)×150μm(w) and 500μm(l)×200μm(w), with height of 60μm. There are also two groups of plane metal electrodes, one with straight needles and another with tilted needles. Those with straight needles have the same sizes of needles as the second plane electrodes based on PI substrate while those with tilted needles, the size of which is 350μm(l)×150μm(w), with height of 60μm, also include a base with side length of 500μm beneath the needle. The angle between needle/base and electrode is 60°.In our study, we used standard MEMS fabrication technology which involves sputtering, photolithography, etching, and electroplating. We also realized three different fabrication processes, analyzed and optimized the process. The general impedance of a single plane electrode tested in 0.9% saline solution is 100 k? ~ 100 ?, at the frequency from 0.1Hz to 1000 Hz. In the following vivo human experiment, the effects of the plane electrode and conventional wet electrode have been compared. The comparison among various types of plane electrodes has also been made. It has been proved that EEG signals can be recorded by every type of electrodes, of which the second batch of plane electrodes based on PI substrate as well as plane metal electrodes can achieve better recordings, especially those assembled by 6-10 pieces.更多还原