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International Conference on computer Integrated Manufacturing

作者： M.B. McIlrath D.S. Boning Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

Concepts and data structures which can be used to allow effective linkage between manufacturing and design activities and hence facilitate improved process development are proposed. Central to the approach is the use of a common representation of the manufacturing process flow, used throughout the life-cycle of the process, including conceptual design, simulation, manufacturing, analysis, and maintenance. The overall architecture provides for the incorporation of models of the manufacturing equipment as well as idealized process models in a coherent way to support flexible, portable semiconductor-manufacturing processes. The authors identify the most important aspects of such a process-flow representation and describe the role of the representation in the computer-integrated manufacturing system in use in their semiconductor IC fabrication facility.< >

关键词： Process design Manufacturing processes Semiconductor device manufacture Virtual manufacturing Semiconductor process modeling Data structures Couplings Analytical models computer architecture Flexible manufacturing systems

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Friction and wear in microfabricated harmonic side-drive motors

Friction and wear in microfabricated harmonic side-drive mot...

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IEEE Workshop on Solid-State Sensor and Actuator

作者： M. Mehregany S.D. Senturia J.H. Lang Microsystems Technology Laboratories Laboratory for Electromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

Polysilicon variable-capacitance rotary harmonic side-drive micromotors and results from operational and frictional studies of these motors are described. Quantitative studies of wear under electric excitation are also reported. Voltages as low as 26 V across 1.5- mu m gaps are sufficient for operation. Frictional force estimates of 0.15 mu N at the bushings and 0.04 mu N in the bearings are obtained from measurements of stopping voltages. Extended operation of these motors to near 100 million wobble cycles at excitation frequencies of 10000 r.p.m. and 25000 r.p.m. for operational durations of 150 h and 71 h, respectively, are studied. The results indicate that bearing wear is significant and results in changes in the gear ratio of the motors by as much as 20%. Typical gear ratios are near 90 at the start of motor operation and decrease to about 70 as the bearings wear out.< >

关键词： Friction Micromotors Rotors Insulators Stators Contacts Force measurement Gears Micromechanical devices Testing

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A CAD architecture for microelectromechanical systems

A CAD architecture for microelectromechanical systems

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IEEE International Conference on Micro Electro Mechanical Systems

作者： F. Maseeh R.M. Harris S.D. Senturia MIT Cambridge MA USA Department of Electrical Engineering and Computer Science Microsystems Technology Laboratories Massachusetts Institute of Technology Cambridge MA USA

A CAD architecture for microelectromechanical systems is presented in which conventional mask layout and process simulation tools are linked to three-dimensional mechanical CAD and finite-element tools for analysis and simulation. The architecture is exercised by an elementary example on the stress-induced curvature of an oxidized silicon wafer. An architecture for an object-oriented material property simulator in which material properties and their process dependence are stored and are accessed based on the specific process conditions is also presented.< >

关键词： Microelectromechanical systems Object oriented modeling Material properties Solid modeling Analytical models Predictive models Packaging Computational modeling computer simulation Silicon

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A microfabricated three-degree-of-freedom parallel mechanism

A microfabricated three-degree-of-freedom parallel mechanism

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IEEE International Conference on Micro Electro Mechanical Systems

作者： F. Behi M. Mehregany K.J. Gabriel Robotics Research Department Machine Perception Research Department AT and T Bell Laboratories Inc. Holmdel NJ USA Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Tokyo Japan

A microfabricated, three-degree-of-freedom, passive, closed-chain, planar mechanism with the potential for low-torque precision positioning applications is presented. A parallel-link mechanism design is selected rather than a serial-link implementation, since parallel-link mechanisms can operate with stationary actuators and are more rigid than their serial counterparts. Polysilicon surface micromachining is used to fabricate a mechanism which has a total area of 0.13 mm/sup 2/ and a workspace of approximately 0.01 mm/sup 2/. The fabrication process for the mechanism is described, identifying the effect on device performance of constraints imposed by the microfabrication; most notably joint clearances, component nonplanarity, and residual-stress-induced linkage deformations. The requisite formulations for the kinematics and dynamics of the device are presented which, in conjunction with the documented measurements of friction on structures of similar geometry and material, indicate that the dominant torque loads are due to friction.< >

关键词： Fabrication Micromotors Couplings Kinematics Actuators Friction Silicon Micromachining Torque measurement Appropriate technology

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Operation of microfabricated harmonic and ordinary side-drive motors

Operation of microfabricated harmonic and ordinary side-driv...

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IEEE International Conference on Micro Electro Mechanical Systems

作者： M. Megregany P. Nagarkar S.D. Senturia J.H. Lang Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Laboratory for Electromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

A variable-capacitance harmonic side-drive motor is presented and the operation of this motor and ordinary variable-capacitance side-drive motors without the need for air-levitation assist is reported. Native oxide formation on motor polysilicon surfaces, resulting from the clamping of the rotor to the shield beneath it, is identified as the cause of motor operational failure. With proper release and testing directed at minimizing this oxide formation, the motors can be readily operated. Operational characteristics of the micromotors, including the role of rotor electric shielding, speed, and frictional effects, are studied. For the side-drive motors, measurements of stopping and starting voltages indicate that the drive torque required to sustain motor operation is 5-7 pN-m, while that required to initiate motor operation after a 30 second rest is nearly twice as high.< >

关键词： Micromotors Rotors Contacts Clamps Stators laboratories Testing Electrostatic levitation Torque measurement Voltage

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MONITORING THE CURE OF A COMPOSITE MATRIX RESIN WITH MICRODIELECTROMETRY

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POLYMER engineering AND science 1989年第5期29卷 290-294页

作者： BIDSTRUP, WW SENTURIA, SD Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139

This paper presents a study of the cure of glass and graphite fiber epoxy composites using dielectric monitoring techniques. Initial results reported here deal with the neat resin and the relationship between its cond... 详细信息

关键词： Composite Materials

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Design and fabrication of movable silicon plates suspended by flexible supports

Design and fabrication of movable silicon plates suspended b...

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IEEE International Conference on Micro Electro Mechanical Systems

作者： M.G. Allen M. Scheidl R.L. Smith Microsystems Technology Laboratories Massachusetts Institute of Technology Cambridge MA USA Department of Electrical Engineering and Computer Science University of California Davis Davis CA USA

A process for fabricating silicon plates of varying thicknesses suspended by thin, flexible polyimide arms has been developed. The process uses bulk micromachining techniques and consists of four steps: a diaphragm etch from the back of the wafer; a trench etch from the front side (to define the plates); deposition and patterning of the plate support beams; and a self-aligned backside plasma etch to release the plates. The authors have used this process to fabricate square silicon plates two millimeters on a side and 7-10- mu m-thick suspended by polyimide beams 500- mu m long, 4- mu m thick, and 100-200- mu m wide. By evaporating aluminum on the topside of the plates, it was possible to deflect them electrostatically approximately 60 mu m at 40 V applied voltage. These structures were designed for application as micromachined mirrors, although their sensitivity to motion and electrical and thermal isolation suggest other potential applications such as gas sensors, flow sensors, and accelerometers.< >

关键词： Fabrication Silicon Etching Polyimides Gas detectors Arm Micromachining Particle beams Plasma applications Aluminum

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A DIGITAL READOUT TECHNIQUE FOR CAPACITIVE SENSOR APPLICATIONS

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 1988年第4期23卷 972-977页

作者： KUNG, JT LEE, HS HOWE, RT IEEE Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology

The difference between two capacitors is measured digitally using a charge redistribution technique incorporating a comparator, MOS switches, a successive approximation register, and a digital-to-analog converter. The technique is insensitive to comparator offset and parasitic capacitance, and the effect of MOS switch charge injection is measured and canceled. Extensive measurements have been made from test chips fabricated in 3- mu m CMOS technology. Detection of percent differences of >0.5% on 20-100-fF capacitors has been successfully demonstrated.

关键词： mos Oncogenes Parasitic capacitance Capacitors Percent digital to analog converters COMPARATORS test chip METAL OXIDE SEMICONDUCTORS successive approximation register digitally Switches charge injection

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Surface-micromachining processes for electrostatic microactuator fabrication

Surface-micromachining processes for electrostatic microactu...

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IEEE Workshop on Solid-State Sensor and Actuator

作者： T.A. Lober R.T. Howe Department of Electrical Engineering and Computer Science Microsystems Technology Laboratories Massachusetts Institute of Technology Cambridge MA USA Berkeley Sensor & Actuator Center Department of Electrical Engineering and Computer Sciences University of California Berkeley CA USA

Etch characteristics are discussed of three forms of hydrofluoric acid, used as the micromachining etchant for fabricating a rotary variable-capacitance micromotor structure from polycrystalline silicon (poly-Si) thin films. Low-pressure chemically vapor deposited SiO/sub 2/ (LPCVD LTO) is used to form the sacrificial layers and LPCVD Si/sub 3/N/sub 4/ is used as an electrical isolation layer for the micromachined structure. 7:1, NH/sub 4/F:HF buffered HF (BHF), 48 wt.% concentrated hydrofluoric acid (LHF), and HF vapor in air (VHF) are evaluated at 20 degrees C for etch rate and selectivity, and attack of four types of LPCVD poly-Si films; POCl/sub 3/-doped or undoped, with or without 1150 degrees C annealing. Both BHF and VHF are found to damage POCl/sub 3/-doped poly-Si films, possibly by attack of grain boundaries. VHF is found to be effective for micromachining suspended structures since it avoids deformation of microstructures due to surface tension effects during drying after wet etching with LHF or BHF.< >

关键词： Electrostatics Microactuators Etching Micromachining Hafnium Micromotors Silicon Semiconductor thin films Chemicals Semiconductor films

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NOVEL MICROSTRUCTURES FOR THE INSITU MEASUREMENT OF MECHANICAL-PROPERTIES OF THIN-FILMS

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JOURNAL OF APPLIED PHYSICS 1987年第9期62卷 3579-3584页

作者： MEHREGANY, M HOWE, RT SENTURIA, SD Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139

This paper discusses microfabricated structures designed for the i n s i t u measurement of the mechanical properties of thin films under residual tensile stress. The film is deposited and patterned on a (100) silicon substrate in which 5‐μm‐thick diaphragms have been fabricated. When the silicon diaphragm is etched from the backside in an SF₆ plasma, the microstructures are released and deform under the residual tension. Measurement of this deformation in conjunction with appropriate mechanical models determines the mechanical properties of interest. We have used these structures to study benzophenonetetracarboxylicdianhidride‐oxydianiline/metaphenylene‐diamine polyimide films. Typical value for the residual stress to modulus ratio in this case was determined to be 0.011±0.001 while the ultimate strain at break was found to be 4.5% for 5.5‐μm‐thick films. For thicker films (8.5 μm), the film did not fail until 8% strain was reached.

关键词： Thin film structure Mechanical properties Silicon Thin film deposition Microstructural properties

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