用于红外探测的微型悬臂梁的结构模拟

一种用MEMS微加工技术制造的微型悬臂梁已经开始应用于红外探测技术中,悬臂梁由双层材料构成,衬底由硅、氮化硅等半导体材料制作,另一层则是一种热敏金属材料薄膜.在没有红外辐射情况下,悬臂梁的两侧表面应力是平衡的,而一旦有红外辐射到一侧的热敏薄膜材料后,引发该材料膨胀,迫使微型悬臂梁发生弯曲变形.用有限元分析软件ANSYS对该悬臂梁进行模拟仿真,改变结构参数,观察灵敏度的变化情况.除灵敏度外,还给出了悬臂梁的温度场分布和应力场分布图.获得的数据证明结构参数的设计对微型悬臂梁的灵敏度至关重要.     

基于微型悬臂梁的发电机制探索

微机电系统(MEMS)微型化过程中,要求电源装置也必须向微型化发展.在现有微电源研究基础上,结合微型硅悬臂梁的力学分析以及压电晶体材料压电效应特性,提出一种新的压电陶瓷(PZT)微型硅悬臂梁发电装置.借助微型硅悬臂梁质量块的振动和PZT的正压电效应,实现振动机械能向电能转换.该装置结构简单、体积小、质量小,可以用MEMS集成加工工艺实现结构加工,因此与其他微型MEMS器件可以集成在一个基础上.     

碳纳米管压阻微悬臂梁红外热探测器的研究

研究了压阻复合层微机械悬臂梁红外探测器的热挠曲理论模型。利用IC工艺和微机械加工技术设计制作了一种硅/铝/碳纳米管三层微机械悬臂梁红外探测器,该探测器基于硅和铝两种材料热膨胀系数的差异,存在双物质效应,不同温度下梁的挠度不同,其形变可通过梁根部的压敏电桥检测。为提高探测器的红外吸收特性,实验探索出了在微机械悬臂梁上涂敷碳纳米管吸热层的工艺方法。实验研究了具有碳纳米管薄膜吸热层的三层微机械悬臂梁红外热探测器对红外辐射的响应规律,结果表明涂敷碳纳米管吸热层使响应灵敏度提高近一倍。     

集成硅微悬臂梁融合式传感器制造技术

简要地描述了以各种微结构的硅悬臂梁作为敏感元件构成的不同用途的新型融合式传感器及其列阵；介绍了硅微悬臂梁融合式传感器的设计和制造工艺；对笔者正在研究的硅微悬臂梁与光纤组合式列阵感器作了初步的报道。研究结果表明这是一种很有前途的技术。     

基于PZT薄膜的集成式微悬臂梁结构设计与制作

设计了基于PZT压电薄膜的双层和双片压电微悬臂梁结构,利用压电材料的正压电效应和逆压电效应,通过两个压电元件实现传感和执行功能的集成.悬臂梁结构采用体硅加工工艺制作,锆钛酸铅(Pb(Zr,Ti)O3,PZT)压电薄膜采用sol-gel方法在Pt/Ti/SiO2/Si衬底上制作,压电薄膜具有完整的钙钛矿结构和(111)择优取向.为了提高悬臂梁的性能和制作成品率,对制作微悬臂梁的关键工艺进行了优化.     

一种硅/二氧化硅双层微悬臂梁温度传感器

利用IC工艺和微机械加工技术制作了一种硅／二氧化硅双层微悬臂梁温度传感器。基于硅和二氧化硅两种材料热膨胀系数的差异，不同温度下梁的挠度不同，其形变可通过位于梁根部的压敏电桥检测。理论计算和实验结果表明：压敏电桥输出电压与温度成线性关系。对器件结构进行了优化设计，实验探索了提高传感器测量重复性的时效处理工艺。该温度传感器可用于瞬态温度的测量。     

基于微悬臂梁的传感技术研究

本文对基于微悬臂梁的传感技术从四方面展开讨论,分别介绍了微悬臂梁的制造工艺,修饰技术,激励、检测和控制技术,以及与其它电路的工艺集成技术。微悬臂梁在液体中,工作在动态模式时,品质因数的提高问题一直是国内外研究的焦点。本文的重点便是介绍国际上最新出现的两种品质因子控制技术,一种是对微悬臂梁的材料进行了改进,使其在水溶液的品质因数达到40,另一种是把液体环境转移到悬臂梁内部,使其在水溶液中的品质因数达到700。     

多次掩模湿法腐蚀硅微加工过程的蒙特卡罗仿真

探讨利用蒙特卡罗 (Monte Carlo, MC) 法模拟硅微加工各向异性湿法腐蚀的仿真,实现连续多次掩模,多步硅微加工工艺过程的仿真.介绍MC法的使用特点及其在湿法腐蚀硅微加工中的应用,仿真使用腐蚀概率方程确定表面原子适当的MC转移概率,模拟方法支持氧化硅和氮化硅掩模层作用下的各向异性腐蚀加工和多次掩模的传递过程.编制的仿真程序通过模拟一个原子力显微镜探针阵列多掩模连续6步工艺的硅微加工过程验证了MC法的正确性.     

硅微构件的弹性模量和残余内应力的测试

叙述了利用硅悬臂梁和两端固定梁微构件进行硅微薄膜材料的弹性模量和残余内应力的测试方法。本方法利用简单的光学装置,通过测量悬臂梁和两端固定梁的一阶谐振频率,分别求弹性模量和残余内应力。本方法测量系统简单,试样制作方便。本试验获得（100）面<110>方向单晶硅微薄膜的弹性模量为128GPa,残余内应力为74.7MPa.     

气囊驱动硅微针尖阵列微量药物输送执行器的研究

论述了一种用于生化微系统中药物释放的系统,即气囊驱动微量药物输送执行器,通过此驱动系统可以达到局部输送药物的目的.利用微针阵列实行局部定时地释放药物、控制药量,微针阵列的研制是微驱动器的关键.执行器的微针部分采用硅-氮化硅-硼硅玻璃-金属(钛、镍、金)材料,利用MEMS技术研制,驱动部分利用硅-PDMS材料作气囊,主要介绍了微针的结构和气囊制作的工艺技术.气囊驱动的微执行器为生化微系统研究提供了一个技术方案,为实现局部定时释放药物、控制药量提供了可行的手段和方法.     

一种基于MEMS技术的新型谐振式微流量传感器

提出了一种新颖的微机械谐振式微流量传感器.该传感器采用电磁激励方式.传感器主要由1个3 μm 厚H型谐振器、1个40 μm厚的悬臂梁平板(2 000 μm×5 000 μm)以及连接平板和框架的2根40 μm厚的支撑梁组成.谐振器采用低应力富硅氮化硅SiN制作,可以方便地使用湿法腐蚀释放谐振器,从而简化工艺流程,提高成品率.文中分析了理论模型、有限元仿真(FEA)、工艺制造和测试结果.测试结果显示,传感器在1 SLM(标准L/min)流量下,频率漂移为500 Hz,分辨率达到5/1 000.但在输出(谐振器频率漂移)和输入(气体流量)间存在二次曲线关系.     

Improvement of thermally induced bending of cantilevers used for atomic force microscopy

The microfabricated silicon nitride cantilevers that are used for atomic force microscopy (AFM) are, unfortunately, sensitive thermometers. They bend with ambient temperature changes and those due to laser heating. The bend can result in displacements for the silicon nitride cantilevers of an order several hundred nanometers at the tip of the cantilever. If, however, the silicon nitride cantilevers are treated by removing the metallization and annealing at 500°C for 30 min, these displacements can be reduced by one or two orders of magnitude. Silicon cantilevers have approximately a one order of magnitude smaller drift than silicon nitride cantilevers as received from vendors and are improved less by treatment.     

Mapping of lateral vibration of the tip in atomic force microscopy at the torsional resonance of the cantilever

Lateral vibration of the tip in atomic force microscopy was mapped at the torsional resonance of the cantilever by attaching a shear piezo element at the base of the cantilever or under the sample. Fixed frequency excitation and self-excitation of torsional motion were implemented. The lateral vibration utilized as measured by an optical lever was in the order of 10 pm to 3 nm, and its frequency approximately 450 kHz for a contact-mode silicon nitride cantilever. The amplitude and phase of the torsional motion of the cantilever was measured by a lock-in-amplifier or a rectifier and plotted in x and y as the sample was raster scanned. The imaging technique gave contrast between graphite terraces, self-assembled monolayer domains, silicon and silicon dioxide, graphite and mica. Changing contrast was observed as silicon islands oxidized in atmosphere, showing that the imaging technique can detect change in lateral tip mobility due to changes occurring near the surface. Torsional self-excitation showed nanometric features of self-assembled monolayer islands due to different lateral dissipation. Dependence of torsional resonance frequency on excitation amplitude, and contrast change due to driving frequency around resonance were observed.     

Study on the grinding behavior of laser-structured grinding in silicon nitride ceramic

Silicon nitride ceramics are extremely difficult and time-consuming to be machined with conventional methods, such as turning and grinding. Laser-assisted machining has been a field of extensive research during the past decade, as it is a promising solution to enhance the machinability of many difficult-to-cut materials, including silicon nitride ceramics. To enhance the processing precision of silicon nitride ceramic grinding, in this work, a method of laser structuring the surface of silicon nitride is proposed. The laser process allows to precisely control the dimensions of the generated features. Therefore, different patterns with equal silicon nitride surface area are produced in order to study the influence of the pattern geometry on the grinding behavior of the silicon nitride. Grinding performance of the structured silicon nitride is tested. The influences of grinding parameters, such as wheel speed and feed rate, are analyzed for their effects on the grinding force, surface roughness. It is found that the procedure of laser-structured silicon nitride has a strong influence on the grinding results. The grooves obtained by laser-structured silicon nitride are favorable for the flow of coolant, and the cracks generated inside the grooves weak the material locally. The laser-structured silicon nitride generally allows for a reduction of grinding forces by up to 63%, and it can effectively reduce the wear of the tool.     

离子束增强沉积薄膜的摩擦磨损行为与结构分析

采用离子束增强沉积（IBED）技术在不锈钢1Cr18Ni9Ti衬底表面生长氮化钛薄膜以及氮离子注入,进行了干滑动摩擦磨损试验与组织结构电镜分析,表明增强沉积膜较离子注入具有更高耐磨性能。     

A study on the fabrication of micro groove on SI wafer using chemical mechanical machining

Materials are either removed from or added to a device, usually in a selective manner with using thin and/or thick film manufacturing processes that transfer the lithographic patterns into integrated circuits (ICs) or three-dimensional micromachines. This study deals with material removal by chemically assisted mechanical micromachining. Two methods are used chemical mechanical machining method are introduced in this paper. One, mechanically assisted chemical etching, is applied to fabricate a micro beam such as cantilever, and another is chemically assisted mechanical micromachining to fabricate microstructure such as micropattern, microchannel. The results are discussed.     

微观摩擦与表面形貌相关性的试验研究

针对微机电系统存在的问题，阐述了微摩擦的测试方法以及表面形貌对微机械中摩擦性能的影响，试验研究了表面形貌对介于宏观和微观之间摩擦行为的影响。试验用研磨的方法在硅片表面制作了不同宽度的条纹，通过UMT微摩擦测试仪研究了在不同速度和载荷下氮化硅陶瓷球和试样间的摩擦行为。试验表明，在硅片上制作出合适的条纹有助于降低摩擦系数，在低载低速下出现了测力梁突然释放弹性变形能的情况，使得摩擦力和载荷不稳定，而且随着表面条纹间距增大，这种现象的频率也越来越高，并通过理论分析解释了这些现象。     

Highly sensitive polymer-based cantilever-sensors for DNA detection

We present a technology for the fabrication of cantilever arrays aimed to develop an integrated biosensor microsystem. The fabrication process is based on spin coating of the photosensitive polymer and near-ultraviolet exposure. Arrays of up to 33 microcantilevers are fabricated in the novel polymer material SU-8. The low Young's modulus of the polymer, 40 times lower than that of silicon, enables to improve the sensitivity of the sensor device for target detection. The mechanical properties of SU-8 cantilevers, such as spring constant, resonant frequency and quality factor are characterized as a function of the dimensions and the medium. The devices have been tested for measurement of the adsorption of single stranded DNA and subsequent interstitial adsorption of lateral spacer molecules. We demonstrate that sensitivity is enhanced by a factor of six compared to that of commercial silicon nitride cantilevers.     

Large Deformation Analysis and Synthesis of Elastic Closed-loop Mechanism Made of a Certain Spring Wire Described by Free Curves

Recently novel mechanisms with compact size and without many mechanical elements such as bearing are strongly required for medical devices such as surgical operation devices. This paper describes analy...     

Mechanical and dynamic characteristics of double and single beam cantilevers for MEMS manipulation

Micro and millimeter-scaled cantilever beams are commonly used to apply and measure microforce and manipulate micro-objects, biological cells, and tissues. In manipulating micro-objects and actuating micro-devices by cantilever beams, sudden application and release of forces are typical, and subject to static and dynamic modes of operation. Therefore, the cantilever’s mechanical behavior and vibration characteristics are vital since they are also used in force sensors and probes. The dynamic behavior of the double beam cantilever (DBC) in micro and millimeter-scaled is explored by varying the length without changing the stiffness and compared with the single beam cantilever (SBC). The dynamic attributes such as mode shape, natural frequency, resonance, and response under the impulse force and Coulomb friction are evaluated numerically. This study will assist in selecting the appropriate type and length of cantilevers in micro and millimeter-scale to manipulate micro-objects, biological cells and tissues, and use in MEMS sensors.