Microactuators and their technologies

This paper gives a brief overview of microactuators, focussing on devices made by microfabrication technologies which are based on silicon processes like photolithography, etching, thin film deposition etc. These technologies enable the miniaturization of electrical devices as well as micromechanisms and microactuators. They can be batch fabricated on large area silicon substrates and represent the smallest available in a vast field of actuators. Mentioning the activation principles and the three main fabrication technologies: bulk micromachining, surface macromachining and moulding, the paper focusses on devices, which made their way into industrial applications or prototypes. The far most developed micro electro-mechanical systems (MEMS) are found in micro-fluidic systems (printheads, microvalves and -pumps) and micro-optical systems (micromirrors, -scanners, -shutters and -switches). They can be combined with microelectronics and microsensors to form an integrated on-chip or hybrid-assembled system. Other MEMS-actuators like microgrippers, microrelays, AFM heads or data storage devices, are promising devices for future medical, biological and technical applications like minimal invasive surgery or the vast field of information storage and distribution.     

A Novel Wafer-Level Hermetic Packaging for MEMS Devices

Some emerging microelectromechanical systems (MEMS) devices such as high-performance inertial sensors and high-speed actuators must be operated in a high vacuum and in order to create this vacuum environment, specific packaging is required. To satisfy this demand, this paper presents a novel method for hermetic and near-vacuum packaging of MEMS devices. We use wafer-level bonding technology to combine with vacuum packaging, simultaneously. For this packaging solution, the wafers with air-guided micro-through-holes were placed on a custom-built design housed in a vacuum chamber maintained at a low-pressure environment of sub-10 mtorr. Packaging structure is then sealed by solder ball reflow process with the lower heating temperature of 300degC to fill up micro-through-hole. Experimental results shown the hermetical packaging technique using solder sealing is adapted to the wafer-level microfabrication process for MEMS devices and can achieve better yield and performance. Thus, this technique is very useful for many applications with high performance and low packaging cost can be obtained due to wafer-level processing.     

The package integration of RF-MEMS switch and control IC for wireless applications

The integration of microelectromechanical systems (MEMS) switch and control integrated circuit (IC) in a single package was developed for use in next-generation portable wireless systems. This packaged radio-frequency (RF) MEMS switch exhibits an insertion loss under -0.4 dB, and isolation greater than -45 dB. This MEMS switch technology has significantly better RF characteristics than conventional PIN diodes or field effect transistor (FET) switches and consumes less power. The RF MEMS switch chip has been integrated with a high voltage charge pump plus control logic chips into a single package to accommodate the low voltage requirements in portable wireless applications. This paper discusses the package assembly process and critical parameters for integration of MEMS devices and bi-complementary metal oxide semiconductor (CMOS) control integrated circuit (IC) into a single package.     

Microelectromechanical systems

The microfabrication techniques used to develop high-performance closed-loop-controlled microelectromechanical systems (MEMS) are discussed. A generalized MEMS could consist of mechanical components, sensors, actuators, and electronics, all integrated in the same environment. Bulk and surface micromachining, substrate bonding, and electroforming in conjunction with X-ray lithography, all integral components of silicon micromachining, are described. The development of a materials base for MEMS and a variety of physical phenomena for microactuator applications that have recently been demonstrated are reviewed. The applications and future trends of MEMS technologies are discussed     

The Lucent LambdaRouter: MEMS technology of the future here today

MEMS devices are beginning to impact almost every area of science and technology. In fields as disparate as wireless communications, automotive design, entertainment, and lightwave systems MEMS is increasingly becoming a key technology. In this article we discuss MEMS devices in general, show how and where they will be used in lightwave systems, and then show in detail how they are allowing a billion dollar business to be born, that of large all-optical crossconnects. In particular we highlight one particular device, the Lucent LambdaRouter, and show how it is built from the chip on up and discuss its performance and applications     

MEMS technology integrated in the CMOS back end

The Nanomech? MEMS technology platform which implements arrays of MEMS devices embedded inside the CMOS back end is described. The key advantages of this integration approach are described in terms of achieving a reliable MEMS technology process within competitive cost requirements, without any need for dedicated process, material and packaging development. The choice of materials is also providing a strong and reliable technology for harsh environment applications where cost is also a key. Data is shown providing a broad picture of the Nanomech? technology and its potentials for applications.     

Biomedical microsystems for minimally invasive diagnosis and treatment

Great significant progress has been made in the development of biomedical microdevices in recent years, and these devices are now playing an important role in diagnosis and therapy. This paper presents a review of applications of microelectromechanical systems (MEMS) devices for in vivo diagnosis and therapy, and endoscopic- and catheter-based interventions. MEMS technology has enabled the further development of advanced biomedical microdevices for use in the human body by integration of sensors, actuators, and electronics into small medical devices for use in the body. In this paper, we discuss three categories of such devices: navigation systems, sensors and actuators for catheters and endoscopes, and other minimally invasive techniques. A brief introduction to principles, device structures, packaging, and related issues is presented.     

MEMS器件在航天领域的应用及发展

介绍了MEMS器件在航天领域的应用及发展,通过航天应用的一些要求和特点,分析了MEMS器件在航天应用中重点关注的一些可靠性问题,如辐射、真空、热冲击和机械振动。根据MEMS器件在当今航天领域的实际应用状况,展望了MEMS器件的前景。提出MEMS器件已成为航天应用领域不可缺的重要器件,在实现系统的小型化、低成本化和性能改善上发挥着巨大的作用。最后预测MEMS器件的发展趋势是取代空间载体、通信和导航平台及有效载荷上体积大而笨重的器件,最终实现航空航天系统的小型化、智能化和集成化。     

Packaging for microelectromechanical and nanoelectromechanical systems

Packaging is a core technology for the advancement of microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). We discuss MEMS packaging challenges in the context of functional interfaces, reliability, modeling and integration. These challenges are application-dependent; therefore, two case studies on accelerometers and BioMEMS are presented for an in-depth illustration. Presently, most NEMS are in the exploratory stage and hence a unique path to identify the relevant packaging issues for these devices has not been determined. We do, however, expect the self-assembly of nano-devices to play a key role in NEMS packaging. We demonstrate this point in two case studies, one on a silicon nanowire biosensor, and the other on self-assembly in molecular biology. MEMS/NEMS have the potential to have a tremendous impact on various sectors such as automotive, aerospace, heavy duty applications, and health care. Packaging engineers have an opportunity to make this impact a reality by developing low-cost, high-performance and high-reliability packaging solutions.     

Large jobs for little devices [microelectromechanical systems]

Microelectromechanical systems (MEMS) may become key components of radio frequency devices, particularly in the mobile marketplace. In filters, they may lower radio size and power consumption while increasing sensitivity. In switches, they could herald the construction of cheaper, electronically steerable antennas for radar and communications applications. MEMS are electromechanical devices with tiny moving parts. They can be built using IC-compatible materials, such as polysilicon, allowing their integration on a silicon chip, side-by-side with semiconductor circuits. Experimental filters are now reaching hundreds of megahertz, and operation up in the gigahertz ranges needed for most wireless and some satellite communications should be feasible. Their ability to kill several birds with one stone is making them very attractive to researchers and developers     

Microfabricated Drug Delivery Devices: Design,Fabrication, and Applications

Microfabrication technology has enabled the development of novel controlled‐release devices that possess an integration of structural, mechanical, and perhaps electronic features, which may address challenges associated with conventional delivery systems. In this feature article, microfabricated devices are described in terms of materials, mechanical design, working principles, and fabrication methods, all of which are key features for production of multifunctional, highly effective drug delivery systems. In addition, the current status and future prospects of different types of microfabricated devices for controlled drug delivery are summarized and analyzed with an emphasis on various routes of administration including ocular, oral, transdermal, and implantable systems. It is likely that microfabrication technology will continue to offer new, alternative solutions to design advanced and sophisticated drug delivery devices that promise to significantly improve medical care.     

A fully integrated SOI RF MEMS technology for system-on-a-chip applications

In this paper, a silicon-on-insulator (SOI) radio-frequency (RF) microelectromechanical systems (MEMS) technology compatible with CMOS and high-voltage devices for system-on-a-chip applications is experimentally demonstrated for the first time. This technology allows the integration of RF MEMS switches with driver and processing circuits for single-chip communication applications. The SOI high-voltage device (0.7-/spl mu/m channel length, 2-/spl mu/m drift length, and over 35-V breakdown voltage), CMOS devices (0.7-/spl mu/m channel length and 1.3/-1.2 V threshold voltage), and RF MEMS capacitive switch (insertion loss 0.14 dB at 5 GHz and isolation 9.5 dB at 5 GHz) are designed and fabricated to show the feasibility of building fully integrated RF systems. The performance of the fabricated RF MEMS capacitive switches on low-resistivity and high-resistivity SOI substrates will also be compared.     

微电子机械系统

概述了微电子机械系统（MEMS）的特点,理论和技术基础。详细介绍了微型传感器、微型执行器、微型光机电系统（MOEMS）、微型生物化学芯片、微型机器人、微型飞行器、微型动力系统和纳米电子机械系统等主要MEMS器件和系统及这些器件在个人运载工具导航、系统监控与故障预防、环境感知、小型分析仪、生物医疗器械和航空航天等领域的应用,最后简述了MEMS技术的发展趋势与我国的发展现状。     

Microelectromechanical systems and system-on-chip connectivity

The interconnection of microelectromechanical systems (MEMS) and other devices to a system-on-chip (SoC) implementation is described. MEMS technology can be used to fabricate both application specific devices and the associated micropackaging system that will allow for the integration of devices or circuits, made with non-compatible technologies, with a SoC environment. In the primary example presented, MEMS technology has been used to develop an acoustical array sensor for a hearing instrument application and also to provide a custom micropackaging solution suitable for in-the-ear canal implantation. A MEMS based modular micropackaging solution consisting of MEMS socket submodules and an insertable/removable microbus card has been developed to provide the necessary packaging and connectivity requirements. The modular socket concept can also be used for many other purposes, such as temporarily connecting a CMOS die to a SoC implementation of a die tester using MEMS based cantilevered bridge-type microspring contacts to provide connectivity to the die under test.     

BioMEMS和人体植入式生物微系统

MEMS技术在医药科学技术的一个重要应用是植入人体内的生物微系统(BioMEMS)。该系统集微传感器、微驱动器、微流体系统、微光学系统及微机械元件于一体,用于体内器官的诊断、体内器官功能修复或替代,其治疗效果确切,已成为关系本世纪医学与人类健康进步的重要领域。本文介绍了近年来不同功能类别植入式BioMEMS的发展状况,说明了MEMS工艺、方法及材料在此领域的应用。     

碳化硅材料在微电子机械系统中的应用

碳化硅材料包括单晶碳化硅、多晶碳化硅、无定形碳化硅等,由于其显著的材料特性,如耐热、耐磨、化学惰性和高硬度等,近年来在微电子机械系统(MEMS)领域受到越来越多的关注。应用特定的工艺条件将碳化硅材料制成MEMS器件,可以在某些特殊条件下使用,克服了常规材料本身的局限性,从而为碳化硅材料的应用开发了新的领域。追踪这一国际热点研究问题,针对以上几种不同形态材料,分别举例说明了它们在MEMS领域应用的进展情况。     

Advances in integrated 2D MEMS-based solutions for optical network applications

Reduction of installation and operational costs are currently the driving force behind the implementation of optical networks. 2D MEMS technology plays an important role in the development of these network systems with several applications, including optical cross-connects, protection switching, optical add-drop multiplexing and wavelength switching. The optical design and packaging technology that has been developed for 2D MEMS has resulted in a flexible platform that can be used to manufacture highly integrated fiber optic devices.     

Packaging of nanostructured microelectromechanical systems microtriode devices

Combining the world of microelectromechanical systems (MEMS) with that of nano can lead to new devices with unique or advanced functionalities. Carbon nanotubes are fascinating new nanomaterials with many interesting physical, chemical, and electronic properties and potential new applications. We have incorporated nanotubes into the MEMS structure as patterned, cold-cathode field emitters to create on-chip, miniature vacuum tubes of microtriodes that can be useful for high-frequency microwave communications. Proper bonding and assembly processes were essential in providing reliable electrical connections and improved amplification performances.     

脉冲激光MEMS加工技术

阐述了脉冲激光微加工技术及其在微机电系统 (MEMS)加工中的应用。脉冲激光微加工技术能够制作出三维微型结构并具有微米 /亚微米加工精度 ,且适用于多种材料 ,与传统的微细加工技术如光刻、刻蚀、体硅和面硅加工技术等相比具有其独到之处。进一步阐述了基于激光烧蚀的脉冲激光直接微加工技术、激光 LIGA技术、激光辅助沉积与刻蚀技术以及MEMS的激光辅助操控及装配技术     

埋置型叠层微系统封装技术

包含微机电系统(MEMS)混合元器件的埋置型叠层封装,此封装工艺为目前用于微电子封装的挠曲基板上芯片(COF)工艺的衍生物。COF是一种高性能、多芯片封装工艺技术,在此封装中把芯片包入模塑塑料基板中,通过在元器件上形成的薄膜结构构成互连。研究的激光融除工艺能够使所选择的COF叠层区域有效融除,而对封装的MEMS器件影响最小。对用于标准的COF工艺的融除程序进行分析和特征描述,以便设计一种新的对裸露的MEMS器件热损坏的潜在性最小的程序。COF/MEMS封装技术非常适合于诸如微光学及无线射频器件等很多微系统封装的应用。