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All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Packaging Technology Designed, Fabricated, and Assembled for High-Temperature SiC Microsystems

A series of ceramic substrates and thick-film metalization-based prototype microsystem packages designed for silicon carbide (SiC) high-temperature microsystems have been developed for operation in 500 C harsh environments. These prototype packages were designed, fabricated, and assembled at the NASA Glenn Research Center. Both the electrical interconnection system and the die-attach scheme for this packaging system have been tested extensively at high temperatures. Printed circuit boards used to interconnect these chip-level packages and passive components also are being fabricated and tested. NASA space and aeronautical missions need harsh-environment, especially high-temperature, operable microsystems for probing the inner solar planets and for in situ monitoring and control of next-generation aeronautical engines. Various SiC high-temperature-operable microelectromechanical system (MEMS) sensors, actuators, and electronics have been demonstrated at temperatures as high as 600 C, but most of these devices were demonstrated only in the laboratory environment partially because systematic packaging technology for supporting these devices at temperatures of 500 C and beyond was not available. Thus, the development of a systematic high-temperature packaging technology is essential for both in situ testing and the commercialization of high-temperature SiC MEMS. Researchers at Glenn developed new prototype packages for high-temperature microsystems using ceramic substrates (aluminum nitride and 96- and 90-wt% aluminum oxides) and gold (Au) thick-film metalization. Packaging components, which include a thick-film metalization-based wirebond interconnection system and a low-electrical-resistance SiC die-attachment scheme, have been tested at temperatures up to 500 C. The interconnection system composed of Au thick-film printed wire and 1-mil Au wire bond was tested in 500 C oxidizing air with and without 50-mA direct current for over 5000 hr. The Au thick-film metalization-based wirebond electrical interconnection system was also tested in an extremely dynamic thermal environment to assess thermal reliability. The I-V curve1 of a SiC high-temperature diode was measured in oxidizing air at 500 C for 1000 hr to electrically test the Au thick-film material-based die-attach assembly.

Chen, Liang-Yu↗
NASA NTRSDate not supplied

Characterizations of Optimized Microshutter Arrays for Space Borne Observatory Applications

We report the latest design, fabrication, and characterization result of the Next-Generation Microshutter Arrays (NGMSA) for space borne observatory applications. Our improved blade design aims to reduce the counter torque induced by the potential on the opposing wall to eliminate the torque bump, and thus enables pure electrostatic actuation for more reliable and stable microshutter operations. This paper presents the experimental performances of micro-fabricated microshutter arrays with varying design parameters and compares the results with simulation predictions.

Electrostatic↗
NASA NTRS2005

Printed Antennas Made Reconfigurable by Use of MEMS Switches

A class of reconfigurable microwave antennas now undergoing development comprise fairly conventional printed-circuit feed elements and radiating patches integrated with novel switches containing actuators of the microelectromechanical systems (MEMS) type. In comparison with solid-state electronic control devices incorporated into some prior printed microwave antennas, the MEMS-based switches in these antennas impose lower insertion losses and consume less power. Because the radio-frequency responses of the MEMS switches are more nearly linear, they introduce less signal distortion. In addition, construction and operation are simplified because only a single DC bias line is needed to control each MEMS actuator.

Simons, Rainee N.↗
NASA NTRS2009

NASA Tech Briefs, March 2009

Topics covered include: Improved Instrument for Detecting Water and Ice in Soil; Real-Time Detection of Dust Devils from Pressure Readings; Determining Surface Roughness in Urban Areas Using Lidar Data; DSN Data Visualization Suite; Hamming and Accumulator Codes Concatenated with MPSK or QAM; Wide-Angle-Scanning Reflectarray Antennas Actuated by MEMS; Biasable Subharmonic Membrane Mixer for 520 to 600 GHz; Hardware Implementation of Serially Concatenated PPM Decoder; Symbolic Processing Combined with Model-Based Reasoning; Presentation Extensions of the SOAP; Spreadsheets for Analyzing and Optimizing Space Missions; Processing Ocean Images to Detect Large Drift Nets; Alternative Packaging for Back-Illuminated Imagers; Diamond Machining of an Off-Axis Biconic Aspherical Mirror; Laser Ablation Increases PEM/Catalyst Interfacial Area; Damage Detection and Self-Repair in Inflatable/Deployable Structures; Polyimide/Glass Composite High-Temperature Insulation; Nanocomposite Strain Gauges Having Small TCRs; Quick-Connect Windowed Non-Stick Penetrator Tips for Rapid Sampling; Modeling Unsteady Cavitation and Dynamic Loads in Turbopumps; Continuous-Flow System Produces Medical-Grade Water; Discrimination of Spore-Forming Bacilli Using spoIVA; nBn Infrared Detector Containing Graded Absorption Layer; Atomic References for Measuring Small Accelerations; Ultra-Broad-Band Optical Parametric Amplifier or Oscillator; Particle-Image Velocimeter Having Large Depth of Field; Enhancing SERS by Means of Supramolecular Charge Transfer; Improving 3D Wavelet-Based Compression of Hyperspectral Images; Improved Signal Chains for Readout of CMOS Imagers; SOI CMOS Imager with Suppression of Cross-Talk; Error-Rate Bounds for Coded PPM on a Poisson Channel; Biomorphic Multi-Agent Architecture for Persistent Computing; and Using Covariance Analysis to Assess Pointing Performance.

Source record↗
NASA NTRS1996

Microelectromechanical Systems for Aerodynamics Applications

Microelectromechanical systems (MEMS) embody the integration of sensors, actuators, and electronics on a single substrate using integrated circuit fabrication techniques and compatible micromachining processes. Silicon and its derivatives form the material base for the MEMS technology. MEMS devices, including micro-sensors and micro-actuators, are attractive because they can be made small (characteristic dimension about microns), be produced in large numbers with uniform performance, include electronics for high performance and sophisticated functionality, and be inexpensive. MEMS pressure sensors, wall-shear-stress sensors, and micromachined hot-wires are nearing application in aeronautics. MEMS actuators face a tougher challenge since they have to be scaled (up) to the physical phenomena that are being controlled. MEMS actuators are proposed, for example, for controlling the small structures in a turbulent boundary layer, for aircraft control, for cooling, and for mixing enhancement. Data acquisition or control logistics require integration of electronics along with the transducer elements with appropriate consideration of analog-to-digital conversion, multiplexing, and telemetry. Altogether, MEMS technology offers exciting opportunities for aerodynamics applications both in wind tunnels and in flight

Mehregany, Mehran↗
NASA NTRS2001

MEMS Memory Elements

This paper presents a design example that illustrates the potential of microelectromechanical systems (MEMS) to perform the mechanical positioning required for addressing stored data and to enable an entirely new mechanism for reading and writing magnetic data. Specifically, MEMS sensors and actuators can be used to achieve active servo control of the separation between magnetic probe tips and a media surface with sub-nanometer accuracy. This allows mechanical position to be used to selectively write magnetic marks in a continuous thin-film magnetic media. In addition, MEMS sensors can be used to measure the separation between a magnetic probe tip and the media with a noise floor of roughly 22 picometers, allowing them to be used as position sensors in a magnetic force microscope (MFM) style data detection system.

Carley, L. Richard↗
NASA NTRS2007

Microstrip Antenna Arrays on Multilayer LCP Substrates

A research and development effort now underway is directed toward satisfying requirements for a new type of relatively inexpensive, lightweight, microwave antenna array and associated circuitry packaged in a thin, flexible sheet that can readily be mounted on a curved or flat rigid or semi-rigid surface. A representative package of this type consists of microwave antenna circuitry embedded in and/or on a multilayer liquid- crystal polymer (LCP) substrate. The circuitry typically includes an array of printed metal microstrip patch antenna elements and their feedlines on one or more of the LCP layer(s). The circuitry can also include such components as electrostatically actuated microelectromechanical systems (MEMS) switches for connecting and disconnecting antenna elements and feedlines. In addition, the circuitry can include switchable phase shifters described below. LCPs were chosen over other flexible substrate materials because they have properties that are especially attractive for high-performance microwave applications. These properties include low permittivity, low loss tangent, low water-absorption coefficient, and low cost. By means of heat treatments, their coefficients of thermal expansion can be tailored to make them more amenable to integration into packages that include other materials. The nature of the flexibility of LCPs is such that large LCP sheets containing antenna arrays can be rolled up, then later easily unrolled and deployed. Figure 1 depicts a prototype three- LCP-layer package containing two four-element, dual-polarization microstrip-patch arrays: one for a frequency of 14 GHz, the other for a frequency of 35 GHz. The 35-GHz patches are embedded on top surface of the middle [15-mil (approx.0.13-mm)-thick] LCP layer; the 14- GHz patches are placed on the top surface of the upper [9-mil (approx. 0.23-mm)-thick] LCP layer. The particular choice of LCP layer thicknesses was made on the basis of extensive analysis of the effects of the thicknesses on cross-polarization levels, bandwidth, and efficiency at each frequency.

Thompson, Dane↗
NASA NTRS2005

Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

The usage of shape memory materials has extended rapidly to many fields, including medical devices, actuators, composites, structures and MEMS devices. For these various applications, shape memory alloys (SMAs) are available in various forms: bulk, wire, ribbon, thin film, and porous. In this work, the focus is on SMA hybrid composites with adaptive-stiffening or morphing functions. These composites are created by using SMA ribbons or wires embedded in a polymeric based composite panel/beam. Adaptive stiffening or morphing is activated via selective resistance heating or uniform thermal loads. To simulate the thermomechanical behavior of these composites, a SMA model was implemented using ABAQUS user element interface and finite element simulations of the systems were studied. Several examples are presented which show that the implemented model can be a very useful design and simulation tool for SMA hybrid composites.

Gao, Xiu-Jie↗
NASA NTRS2001

A-site- and/or B-site-modified PbZrTiO3 materials and (Pb, Sr, Ca, Ba, Mg) (Zr, Ti, Nb, Ta)O3 films having utility in ferroelectric random access memories and high performance thin film microactuators

A modified PbZrTiO.sub.3 perovskite crystal material thin film, wherein the PbZrTiO.sub.3 perovskite crystal material includes crystal lattice A-sites and B-sites at least one of which is modified by the presence of a substituent selected from the group consisting of (i) A-site substituents consisting of Sr, Ca, Ba and Mg, and (ii) B-site substituents selected from the group consisting of Nb and Ta. The perovskite crystal thin film material may be formed by liquid delivery MOCVD from metalorganic precursors of the metal components of the thin film, to form PZT and PSZT, and other piezoelectric and ferroelectric thin film materials. The thin films of the invention have utility in non-volatile ferroelectric memory devices (NV-FeRAMs), and in microelectromechanical systems (MEMS) as sensor and/or actuator elements, e.g., high speed digital system actuators requiring low input power levels.

Roeder, Jeffrey F.↗
NASA NTRS2004

A-SITE-AND/OR B-SITE-MODIFIED PBZRTIO3 MATERIALS AND (PB, SR, CA, BA, MG) (ZR, TI,NB, TA)O3 FILMS HAVING UTILITY IN FERROELECTRIC RANDOM ACCESS MEMORIES AND HIGH PERFORMANCE THIN FILM MICROACTUATORS

A modified PbZrTiO.sub.3 perovskite crystal material thin film, wherein the PbZrTiO.sub.3 perovskite crystal material includes crystal lattice A-sites and B-sites at least one of which is modified by the presence of a substituent selected from the group consisting of (i) A-site substituents consisting of Sr, Ca, Ba and Mg, and (ii) B-site substituents selected from the group consisting of Nb and Ta. The perovskite crystal thin film material may be formed by liquid delivery MOCVD from metalorganic precursors of the metal components of the thin film, to form PZT and PSZT, and other piezoelectric and ferroelectric thin film materials. The thin films of the invention have utility in non-volatile ferroelectric memory devices (NV-FeRAMs), and in microelectromechanical systems (MEMS) as sensor and/or actuator elements, e.g., high speed digital system actuators requiring low input power levels.

Roeder, Jeffrey F.↗
NASA NTRS2008

Four-Point-Latching Microactuator

An experimental inchworm-type linear microactuator is depicted. This microactuator is a successor to one described in "MEMS-Based Piezoelectric/Electrostatic Inchworm Actuator" (NPO-30672), NASA Tech Briefs, Vol. 27, No. 6 (June 2003), page 68. Both actuators are based on the principle of using a piezoelectric transducer operated in alternation with electrostatically actuated clutches to cause a slider to move in small increments. However, the design of the present actuator incorporates several improvements over that of the previous one. The most readily apparent improvement is in geometry and, consequently, in fabrication: In the previous actuator, the inchworm motion was perpendicular to the broad faces of a flat silicon wafer on which the actuator was fabricated, and fabrication involved complex processes to form complex three-dimensional shapes in and on the wafer. In the present actuator, the inchworm motion is parallel to the broad faces of a wafer on which it is fabricated. The components needed to produce the in-plane motion are nearly planar in character and, consequently, easier to fabricate. Other advantages of the present design are described, including that the previous actuator contained two clutches (denoted 'holders' in the cited prior article), the present actuator contains four clutches. The operational sequence of the previous two-clutch actuator is similar. However, the two-clutch configuration is susceptible to tilt of the slider and a consequent large increase in drag. Hence, the primary operational advantages of the present four-point-latching design over the prior two-point-latching design are less drag and greater control robustness arising from greater stability of the orientation of the slider.

Toda, Risaku↗
NASA NTRS2003

NASA Tech Briefs, June 2003

Topics covered include: Nulling Infrared Radiometer for Measuring Temperature; The Ames Power Monitoring System; Hot Films on Ceramic Substrates for Measuring Skin Friction; Probe Without Moving Parts Measures Flow Angle; Detecting Conductive Liquid Leaking from Nonconductive Pipe; Adaptive Suppression of Noise in Voice Communications; High-Performance Solid-State W-Band Power Amplifiers; Microbatteries for Combinatorial Studies of Conventional Lithium-Ion Batteries; Correcting for Beam Aberrations in a Beam-Waveguide Antenna; Advanced Rainbow Solar Photovoltaic Arrays; Metal Side Reflectors for Trapping Light in QWIPs; Software for Collaborative Engineering of Launch Rockets; Software Assists in Extensive Environmental Auditing; Software Supports Distributed Operations via the Internet; Software Estimates Costs of Testing Rocket Engines; yourSky: Custom Sky-Image Mosaics via the Internet; Software for Managing Inventory of Flight Hardware; Lower-Conductivity Thermal-Barrier Coatings; Process for Smoothing an Si Substrate after Etching of SiO2; Flexible Composite-Material Pressure Vessel; Treatment to Destroy Chlorohydrocarbon Liquids in the Ground; Noncircular Cross Sections Could Enhance Mixing in Sprays; Small, Untethered, Mobile Roots for Inspecting Gas Pipes; Paint-Overspray Catcher; Preparation of Regular Specimens for Atom Probes; Inverse Tomo-Lithography for Making Microscopic 3D Parts; Predicting and Preventing Incipient Flameout in Combustors; MEMS-Based Piezoelectric/Electrostatic Inchworm Actuator; Metallized Capillaries as Probes for Raman Spectroscopy; Adaptation of Mesoscale Weather Models to Local Forecasting; Aerodynamic Design using Neural Networks; Combining Multiple Gyroscope Outputs for Increased Accuracy; and Improved Collision-Detection Method for Robotic Manipulator.

Source record↗
NASA NTRS2004

Finite Element Analysis of MEMS Devices

A side-slide actuator and a corrugated diaphragm actuator will be analyzed and optimized this summer. Coupled electrostatic and fluid analyses will also be initiated. Both the side-slide actuator and the corrugated diaphragm actuator will be used to regulate the flow of fuel in a jet engine. Many of the side-slide actuators will be placed on top of a fuel injector that is still in the developmental stage as well. The corrugated diaphragm actuator will also be used to regulate the flow of fuel in fuel injectors. A comparative analysis of the performance matrix of both actuators will be conducted. The side-slide actuator uses the concept of mechanical advantage to regulate the flow of fuel using electrostatic forces. It is made from Nickel, Silicon Carbide, and thin layers of Oxide. The slider will have a hole in the middle that will allow fuel to pass through the hole underneath it. The goal is to regulate the flow of fuel through the inlet. This means that the actuator needs to be designed so that when a voltage is applied to the push rod, the slider will deflect in the x-direction and be able to completely block the inlet and no fuel can pass through. Different voltage levels will be tested. The parameters that are being optimized are the thickness of the diaphragm, what kind of corrugation the diaphragm should have, the length, width, and thickness of the push rod, and what design should be used to return the slider. The current possibilities for a return rod are a built in spring on the slider, a return rod that acts like a spring, or a return rod that is identical to the push rod. The final actuator design should have a push rod that has rotational motion and no translation motion, a push rod thickness that prevents warping due to the slider, and a large ratio of the displacement on the bottom of the push rod to displacement on the top of the push rod. The corrugated diaphragm actuator was optimized last winter and this summer will be spent completing the optimization of the coupled electrostatic and fluid flow parameters. It was found that Nickel is the best material to use for the diaphragm because it has a higher yield strength and allows for a larger stress, deflection and applied pressure. The parameters that were optimized were the wavelength and thickness of the diaphragm.

Corrigan, Jennifer↗
NASA NTRS1998

MEMS Applications in Aerodynamic Measurement Technology

Microelectromechanical systems (MEMS) embodies the integration of sensors, actuators, and electronics on a single substrate using integrated circuit fabrication techniques and compatible bulk and surface micromachining processes. Silicon and its derivatives form the material base for the MEMS technology. MEMS devices, including microsensors and microactuators, are attractive because they can be made small (characteristic dimension about 100 microns), be produced in large numbers with uniform performance, include electronics for high performance and sophisticated functionality, and be inexpensive. For aerodynamic measurements, it is preferred that sensors be small so as to approximate measurement at a point, and in fact, MEMS pressure sensors, wall shear-stress sensors, heat flux sensors and micromachined hot wires are nearing application. For the envisioned application to wind tunnel models, MEMS sensors can be placed on the surface or in very shallow grooves. MEMS devices have often been fabricated on stiff, flat silicon substrates, about 0.5 mm thick, and therefore were not easily mounted on curved surfaces. However, flexible substrates are now available and heat-flux sensor arrays have been wrapped around a curved turbine blade. Electrical leads can also be built into the flexible substrate. Thus MEMS instrumented wind tunnel models do not require deep spanwise grooves for tubes and leads that compromise the strength of conventionally instrumented models. With MEMS, even the electrical leads can potentially be eliminated if telemetry of the signals to an appropriate receiver can be implemented. While semiconductor silicon is well known for its electronic properties, it is also an excellent mechanical material for MEMS applications. However, silicon electronics are limited to operations below about 200 C, and silicon's mechanical properties start to diminish above 400 C. In recent years, silicon carbide (SiC) has emerged as the leading material candidate for applications in high temperature environments and can be used for high-temperature MEMS applications. With SiC, diodes and more complex electronics have been shown to operate to about 600 C, while the mechanical properties of SiC are maintained to much higher temperatures. Even when MEMS devices show benefits in the laboratory, there are many packaging challenges for any aeronautics application. Incorporating MEMS into these applications requires new approaches to packaging that goes beyond traditional integrated circuit (IC) packaging technologies. MEMS must interact mechanically, as well as electrically with their environment, making most traditional chip packaging and mounting techniques inadequate. Wind tunnels operate over wide temperature ranges in an environment that is far from being a 'clean-room.' In flight, aircraft are exposed to natural elements (e.g. rain, sun, ice, insects and dirt) and operational interferences(e.g. cleaning and deicing fluids, and maintenance crews). In propulsion systems applications, MEMS devices will have to operate in environments containing gases with very high temperatures, abrasive particles and combustion products. Hence deployment and packaging that maintains the integrity of the MEMS system is crucial. This paper presents an overview of MEMS fabrication and materials, descriptions of available sensors with more details on those being developed in our laboratories, and a discussion of sensor deployment options for wind tunnel and flight applications.

Reshotko, E.↗
NASA NTRS1993

Advanced microfabrication technologies for microspacecraft

Advanced microfabrication technologies offer the prospect of reducing the weight and size of spacecraft through the use of lighter and stronger materials in conjunction with new mechanical/structural design concepts and design optimization methods. At the same time, electronic components have been scaled down while increasing functional utility. A two-fold benefit is derived for space applications through the use of less expensive components and the lower launch costs associated with lighter components. GE-CRD is actively pursuing research in these key technologies for a wide range of applications including satellites. These key technologies will be reviewed and an update on GE progress will be given. The need to reduce weight and lower cost, while maintaining product quality and reliability are primary drivers in the design of satellites, in general, and microsatellites in particular. For the structural subsystem, these requirements pose a complex design problem unless new mechanical design concepts and computer-aided design optimization methods are employed. Several new concepts, such as battery packs doubling as panel reinforcements and fuel tanks as integral structural members, need to utilized. In addition, new viscoelastic material damping concepts for spacecraft components provide for lighter weight/lower cost designs, while satisfying the structural dynamics requirements. High density interconnect (HDI) technology permits the use of bare IC's on a ceramic substrate with 90 percent active area utilization. A copper/polyimide multilayer structure is the backbone of the technology, which has demonstrated a size/weight reduction of greater than 10x compared to printed circuit board with performance up to the GHz level. HDI modules have exceptional mechanical robustness as evidenced by survival of 180 kg rapid acceleration tests. Microelectromechanical systems (MEMS) are redefining sensors and actuators by miniaturization through micromachining techniques. Sharing many fabrication steps with HDI, we have developed a new technique for surface micromachining of copper/polyimide structures using computer-aided laser patterning.

Ghezzo, M.↗
NASA NTRS1995

Microelectromechanical Systems

Micro-electromechanical systems (MEMS) is an enabling technology that merges computation and communication with sensing and actuation to change the way people and machines interact with the physical world. MEMS is a manufacturing technology that will impact widespread applications including: miniature inertial measurement measurement units for competent munitions and personal navigation; distributed unattended sensors; mass data storage devices; miniature analytical instruments; embedded pressure sensors; non-invasive biomedical sensors; fiber-optics components and networks; distributed aerodynamic control; and on-demand structural strength. The long term goal of ARPA's MEMS program is to merge information processing with sensing and actuation to realize new systems and strategies for both perceiving and controlling systems, processes, and the environment. The MEMS program has three major thrusts: advanced devices and processes, system design, and infrastructure.

Gabriel, Kaigham J.↗