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Journal ArticleDOI

A bulk silicon dissolved wafer process for microelectromechanical devices

TL;DR: In this article, a single-sided bulk silicon dissolved wafer process is described, which has been used to fabricate several different micromechanical structures, including overhanging features.
Abstract: A single-sided bulk silicon dissolved wafer process that has been used to fabricate several different micromechanical structures is described. It involves the simultaneous processing of a glass wafer and a silicon wafer, which are eventually bonded together electrostatically. The silicon wafer is then dissolved to leave heavily boron doped devices attached to the glass substrate. Overhanging features can be fabricated without additional masking steps. It is also possible to fabricate elements with thickness-to-width aspect ratios in excess of 10:1. Measurements of various kinds of laterally driven comb structures processed in this manner, some of which are intended for application in a scanning thermal profilometer, are described. They comprise shuttle masses supported by beams that are 160-360 mu m long, 1-3 mu m wide, and 3-10 mu m thick. Some of the shuttles are mounted with probes that overhang the edge of the die by 250 mu m. Resonant frequencies from 18 to 100 kHz and peak-to-peak displacements up to 18 mu m have been measured. >
Citations
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Journal ArticleDOI
01 Dec 1998
TL;DR: Inertial sensors have seen a steady improvement in their performance, and today, microaccelerometers can resolve accelerations in the micro-g range, while the performance of gyroscopes has improved by a factor of 10/spl times/ every two years during the past eight years.
Abstract: This paper presents a review of silicon micromachined accelerometers and gyroscopes. Following a brief introduction to their operating principles and specifications, various device structures, fabrication, technologies, device designs, packaging, and interface electronics issues, along with the present status in the commercialization of micromachined inertial sensors, are discussed. Inertial sensors have seen a steady improvement in their performance, and today, microaccelerometers can resolve accelerations in the micro-g range, while the performance of gyroscopes has improved by a factor of 10/spl times/ every two years during the past eight years. This impressive drive to higher performance, lower cost, greater functionality, higher levels of integration, and higher volume will continue as new fabrication, circuit, and packaging techniques are developed to meet the ever increasing demand for inertial sensors.

1,816 citations

BookDOI
27 Sep 2001
TL;DR: In this paper, the authors present a detailed overview of the history of the field of flow simulation for MEMS and discuss the current state-of-the-art in this field.
Abstract: Part I: Background and Fundamentals Introduction, Mohamed Gad-el-Hak, University of Notre Dame Scaling of Micromechanical Devices, William Trimmer, Standard MEMS, Inc., and Robert H. Stroud, Aerospace Corporation Mechanical Properties of MEMS Materials, William N. Sharpe, Jr., Johns Hopkins University Flow Physics, Mohamed Gad-el-Hak, University of Notre Dame Integrated Simulation for MEMS: Coupling Flow-Structure-Thermal-Electrical Domains, Robert M. Kirby and George Em Karniadakis, Brown University, and Oleg Mikulchenko and Kartikeya Mayaram, Oregon State University Liquid Flows in Microchannels, Kendra V. Sharp and Ronald J. Adrian, University of Illinois at Urbana-Champaign, Juan G. Santiago and Joshua I. Molho, Stanford University Burnett Simulations of Flows in Microdevices, Ramesh K. Agarwal and Keon-Young Yun, Wichita State University Molecular-Based Microfluidic Simulation Models, Ali Beskok, Texas A&M University Lubrication in MEMS, Kenneth S. Breuer, Brown University Physics of Thin Liquid Films, Alexander Oron, Technion, Israel Bubble/Drop Transport in Microchannels, Hsueh-Chia Chang, University of Notre Dame Fundamentals of Control Theory, Bill Goodwine, University of Notre Dame Model-Based Flow Control for Distributed Architectures, Thomas R. Bewley, University of California, San Diego Soft Computing in Control, Mihir Sen and Bill Goodwine, University of Notre Dame Part II: Design and Fabrication Materials for Microelectromechanical Systems Christian A. Zorman and Mehran Mehregany, Case Western Reserve University MEMS Fabrication, Marc J. Madou, Nanogen, Inc. LIGA and Other Replication Techniques, Marc J. Madou, Nanogen, Inc. X-Ray-Based Fabrication, Todd Christenson, Sandia National Laboratories Electrochemical Fabrication (EFAB), Adam L. Cohen, MEMGen Corporation Fabrication and Characterization of Single-Crystal Silicon Carbide MEMS, Robert S. Okojie, NASA Glenn Research Center Deep Reactive Ion Etching for Bulk Micromachining of Silicon Carbide, Glenn M. Beheim, NASA Glenn Research Center Microfabricated Chemical Sensors for Aerospace Applications, Gary W. Hunter, NASA Glenn Research Center, Chung-Chiun Liu, Case Western Reserve University, and Darby B. Makel, Makel Engineering, Inc. Packaging of Harsh-Environment MEMS Devices, Liang-Yu Chen and Jih-Fen Lei, NASA Glenn Research Center Part III: Applications of MEMS Inertial Sensors, Paul L. Bergstrom, Michigan Technological University, and Gary G. Li, OMM, Inc. Micromachined Pressure Sensors, Jae-Sung Park, Chester Wilson, and Yogesh B. Gianchandani, University of Wisconsin-Madison Sensors and Actuators for Turbulent Flows. Lennart Loefdahl, Chalmers University of Technology, and Mohamed Gad-el-Hak, University of Notre Dame Surface-Micromachined Mechanisms, Andrew D. Oliver and David W. Plummer, Sandia National Laboratories Microrobotics Thorbjoern Ebefors and Goeran Stemme, Royal Institute of Technology, Sweden Microscale Vacuum Pumps, E. Phillip Muntz, University of Southern California, and Stephen E. Vargo, SiWave, Inc. Microdroplet Generators. Fan-Gang Tseng, National Tsing Hua University, Taiwan Micro Heat Pipes and Micro Heat Spreaders, G. P. "Bud" Peterson, Rensselaer Polytechnic Institute Microchannel Heat Sinks, Yitshak Zohar, Hong Kong University of Science and Technology Flow Control, Mohamed Gad-el-Hak, University of Notre Dame) Part IV: The Future Reactive Control for Skin-Friction Reduction, Haecheon Choi, Seoul National University Towards MEMS Autonomous Control of Free-Shear Flows, Ahmed Naguib, Michigan State University Fabrication Technologies for Nanoelectromechanical Systems, Gary H. Bernstein, Holly V. Goodson, and Gregory L. Snider, University of Notre Dame Index

951 citations

Journal ArticleDOI
TL;DR: The use of various materials, such as silicon, glass and polymers, and their related technologies for the manufacturing of simple microchannels and complex systems is discussed in this paper.
Abstract: Microfluidics is an emerging field that has given rise to a large number of scientific and technological developments over the last few years. This review reports on the use of various materials, such as silicon, glass and polymers, and their related technologies for the manufacturing of simple microchannels and complex systems. It also presents the main application fields concerned with the different technologies and the most significant results reported by academic and industrial teams. Finally, it demonstrates the advantage of developing approaches for associating polymer technologies for manufacturing of fluidic elements with integration of active or sensitive elements, particularly silicon devices.

579 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe electrothermal microactuators that generate rectilinear displacements and forces by leveraging deformations caused by localized thermal stresses, where an electric current is passed through a V-shaped beam anchored at both ends, and thermal expansion caused by joule heating pushes the apex outward.
Abstract: This paper describes electrothermal microactuators that generate rectilinear displacements and forces by leveraging deformations caused by localized thermal stresses. In one manifestation, an electric current is passed through a V-shaped beam anchored at both ends, and thermal expansion caused by joule heating pushes the apex outward. Analytical and finite element models of device performance are presented along with measured results of devices fabricated using electroplated Ni and p/sup ++/ Si as structural materials. A maskless process extension for incorporating thermal and electrical isolation is described. Nickel devices with 410-/spl mu/m-long, 6-/spl mu/m-wide, and 3-/spl mu/m-thick beams demonstrate 10 /spl mu/m static displacements at 79 mW input power; silicon devices with 800-/spl mu/m-long, 13.9-/spl mu/m-wide, and 3.7-/spl mu/m-thick beams demonstrate 5 /spl mu/m displacement at 180 mW input power. Cascaded silicon devices using three beams of similar dimensions offer comparable displacement with 50-60% savings in power consumption. The peak output forces generated are estimated to be in the range from 1 to 10 mN for the single beam devices and from 0.1 to 1 mN for the cascaded devices. Measured bandwidths are /spl ap/700 Hz for both. The typical drive voltages used are /spl les/12 V, permitting the use of standard electronic interfaces that are generally inadequate for electrostatic actuators.

373 citations


Cites methods from "A bulk silicon dissolved wafer proc..."

  • ...The Si devices were fabricated by the dissolved wafer process [30]....

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Proceedings ArticleDOI
04 Feb 1992
TL;DR: In this paper, coupled lateral micro-resonators are used to achieve a measured quality factor of 2200 for comb-shape micro-reonators with a measured center frequency of 18.7 kHz and a pass bandwidth of 1.2 kHz.
Abstract: Microelectromechanical filters based on coupled lateral microresonators are demonstrated. This new class of microelectromechanical systems (MEMS) has potential signal-processing applications for filters which require narrow bandwidth (high Q), good signal-to-noise ratio, and stable temperature and aging characteristics. Microfilters presented in this paper are made by surface-micromachining technologies and tested by using an off-chip modulation technique. The frequency range of these filters is from approximately 5 kHz to on the order of 1 MHz for polysilicon microstructures with suspension beams having a 2-/spl mu/m-square cross section. A series-coupled resonator pair, designed for operation at atmospheric pressure, has a measured center frequency of 18.7 kHz and a pass bandwidth of 1.2 kHz. A planar hermetic sealing process has been developed to enable high quality factors for these mechanical filters and make possible wafer-level vacuum encapsulations. This process uses a low-stress silicon nitride shell for vacuum sealing, and experimental results show that a measured quality factor of 2200 for comb-shape microresonators can be achieved.

312 citations

References
More filters
Journal ArticleDOI
TL;DR: In this article, a 2 μm-thick phosphorus-doped low-pressure chemical-vapor-deposited (LPCVD) polysilicon film was used for exciting the resonance.

719 citations

Journal ArticleDOI
TL;DR: In this article, a silicon-processed micro gripper for mounting on a micropositioner was designed and fabricated by combining surface and bulk micromachining, which is electrostatically driven by flexible, interdigitated comb pairs.
Abstract: A silicon-processed microgripper, suitable for mounting on a micropositioner, has been designed and fabricated by combining surface and bulk micromachining. The microgripper consists of a silicon die (7 mm*5 mm), a 1.5 mm long support cantilever, made from boron-doped silicon substrate material (protruding from the die), and a 400 mu m long polysilicon overhanging gripper extending from the end of the support cantilever. The microgripper is electrostatically driven by flexible, interdigitated comb pairs and has significantly smaller feature sizes than have been reported previously for overhanging microstructures. Problems addressed successfully in the microgripper fabrication include the protection of surface-micromachined fine structures during bulk-silicon etching and rinsing. The microgripper has successfully seized several microscopic objects in laboratory experiments. >

223 citations

Journal ArticleDOI
TL;DR: O'Keefemore et al. as discussed by the authors pointed out that the resolution of such a scanning near-field microscope would be limited only by the size of the hole and not by the wavelength of the light.
Abstract: Objects smaller than the wavelengths of visible light are a staple of contemporary science and technology. Biologists study single molecules of protein or DNA; materials scientists examine atomic-scale flaws in crystals; microelectronics engineers lay out circuit patterns only a few tens of atoms thick. Until recently this minute world could be seen only by cumbersome, often destructive methods such as electron microscopy and X-ray diffraction. It lay beyond the reach of any instrument as simple and direct as the familiar light microscope. A family of new microscopes opens this realm to direct observation. The devices can map atomic and molecular shapes, electrical, magnetic and mechanical properties and even temperature variations at a higher resolution than ever before, without the need to modify the specimen or expose it to damaging, high-energy radiation. These new microscoped are typified by the scanning tunneling microscoped. In 1956 J.A. O'Keefe, then of the U.S. Army Mapping Service, proposed a microscope in which light would shine through a tiny hole in an opaque screen, illuminating an object directly in front of the screen. Light transmitted through the specimen or reflect back through the hole would be recorded as the sample was scanned back and forth. O'Keefemore » pointed out that the resolution of such a scanning near-field microscope would be limited only by the size of the hole and not by the wavelength of the light. In principle the device could make superresolving images-images showing details smaller than half a wavelength.« less

191 citations


"A bulk silicon dissolved wafer proc..." refers methods in this paper

  • ...One application that we have targeted for this technology is a scanning thermal profilometer (STP) [ 8 ]....

    [...]

Journal ArticleDOI
TL;DR: An ultraminiature solid-state capacitive pressure sensor that can be mounted in a 0.5mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart is described in this paper.
Abstract: An ultraminiature solid-state capacitive pressure sensor that can be mounted in a 0.5-mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart is described. The transducer consists of a silicon 290*550*1.5- mu m/sup 3/ microdiaphragm surrounded by a 12- mu m-thick silicon supporting rim, both defined by the boron etch-stop technique. The transducer process features a batch wafer-to-glass electrostatic seal followed by the silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. A hybrid interface circuit chip provides a high-level output signal and allows the sensor to be compatible with use on a multisite catheter having only two leads. >

171 citations


"A bulk silicon dissolved wafer proc..." refers background or methods in this paper

  • ...The bonded glass-silicon sandwich is then immersed in ethylene diamine pyrocatechol (EDP) to dissolve away the undoped silicon, leaving the boron doped MEMS mounted on the glass substrate [ 6 ]....

    [...]

  • ...In [ 6 ], the silicon wafer is first selectively etched by KOH to form the bond anchors of the device....

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  • ...The other approach has been to use impurity based etch stops and dopant selective etchants to define the thickness of the MEMS, generally confining it to the range of 1-25 pm [ 6 ], [7]....

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Proceedings ArticleDOI
24 Jun 1991
TL;DR: In this article, a resonant pressure sensor has been fabricated which consists of a single-crystal silicon beam located in the center of a silicon diaphragm and its motion is detected by piezoresistors.
Abstract: A resonant pressure sensor has been fabricated which consists of a single-crystal silicon beam located in the center of a single-crystal silicon diaphragm. The beam is excited electrostatically and its motion are detected by piezoresistors. The structure is fabricated with silicon fusion bonding. Overall measurement accuracies of 0.01% have been achieved. This sensor has been designed to meet the exacting standards required for aerospace air data computers and engine control applications where achievable accuracies of 0.1% absolute pressure are required. The principle of operation is imply to measure the change in resonant frequency of a micromachined silicon beam as the pressure exerted on the sensor's diaphragm is changed. >

91 citations


"A bulk silicon dissolved wafer proc..." refers background in this paper

  • ...One approach has been to grind and polish standard silicon wafers to define the thickness of the MEMS [4], [ 5 ]....

    [...]