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Miniature chemical measurement systems

Description: Prospect of microfabricated monolithic devices that accomplish complete chemical assays is enticing. Early work with microfabricated chemical analysis devices focused on separations methods. More recently reagent manipulation has been integrated with separation devices to create more powerful capabilities. Examples of procedures, other than separations, that have been demonstrated on micromachined structures include reagent mixing, dilution, and reaction, preconcentration through sample stacking and biopolymer tagging for detection. Developments in liquid phase microfabricated chemical analysis devices are reviewed.
Date: December 31, 1996
Creator: Ramsey, J.M.
Partner: UNT Libraries Government Documents Department

Individualized Medicine

Description: The recent focus of microelectromechanical-systems (MEMS) based instrumentation has largely dealt with increasing the throughput of established processes, including drug screening/drug discovery/combinatorial chemistry, or the miniaturization of accepted bench-top instruments. The miniaturization and automation of procedures that were previously performed manually are included in these activities. We suggest that BioMEMS instrumentation will adopt an additional direction, that of providing information and capabilities to the physician that are not available, today.
Date: August 29, 2000
Creator: Mariella, R.
Partner: UNT Libraries Government Documents Department

Tuned cavity magnetometer sensitivity.

Description: We have developed a high sensitivity (<pico Tesla/{radical}Hz), non-cryogenic magnetometer that utilizes a novel optical (interferometric) detection technique. Further miniaturization and low-power operation are key advantages of this magnetometer, when compared to systems using SQUIDs which require liquid Helium temperatures and associated overhead to achieve similar sensitivity levels.
Date: September 1, 2009
Creator: Okandan, Murat & Schwindt, Peter
Partner: UNT Libraries Government Documents Department

Miniaturized Multi-Band Antenna via Element Collocation

Description: The resonant frequency of a microstrip patch antenna may be reduced through the addition of slots in the radiating element. Expanding upon this concept in favor of a significant reduction in the tuned width of the radiator, nearly 60% of the antenna metallization is removed, as seen in the top view of the antenna’s radiating element (shown in red, below, left). To facilitate an increase in the gain of the antenna, the radiator is suspended over the ground plane (green) by an air substrate at a height of 0.250″ while being mechanically supported by 0.030″ thick Rogers RO4003 laminate in the same profile as the element. Although the entire surface of the antenna (red) provides 2.45 GHz operation with insignificant negative effects on performance after material removal, the smaller square microstrip in the middle must be isolated from the additional aperture in order to afford higher frequency operation. A low insertion loss path centered at 2.45 GHz may simultaneously provide considerable attenuation at additional frequencies through the implementation of a series-parallel, resonant reactive path. However, an inductive reactance alone will not permit lower frequency energy to propagate across the intended discontinuity. To mitigate this, a capacitance is introduced in series with the inductor, generating a resonance at 2.45 GHz with minimum forward transmission loss. Four of these reactive pairs are placed between the coplanar elements as shown. Therefore, the aperture of the lower-frequency outer segment includes the smaller radiator while the higher frequency section is isolated from the additional material. In order to avoid cross-polarization losses due to the orientation of a transmitter or receiver in reference to the antenna, circular polarization is realized by a quadrature coupler for each collocated antenna as seen in the bottom view of the antenna (right). To generate electromagnetic radiation concentrically rotating about the ...
Date: June 1, 2012
Creator: Martin, R. P.
Partner: UNT Libraries Government Documents Department

Microstructural evolution of eutectic Au-Sn solder joints

Description: Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.
Date: May 31, 2002
Creator: Song, Ho Geon
Partner: UNT Libraries Government Documents Department

Scanning Probe-Based Processes for Nanometer-Scale Device Fabrication

Description: This is the final report of an LDRD program entitled 'Scanning Probe-Based Processes for Nanometer-Scale Device Fabrication'. This program intends to expand Sandia's expertise in scanning-probe based fabrication and characterization of nanostructures. Our object is to achieve an order of magnitude decrease in feature size compared to conventional fabrication technology. We are exploring approaches to nanostructure fabrication and characterization using scanning probe-based (STM, AFM). We also are developing numerical simulations of localized electric field and emission current to explore mechanisms and characterize limits to processing techniques. We emphasize novel fabrication processes and characterization of physical, chemical and electronic effects in nanostructures.
Date: January 1, 1999
Creator: Adams, D. P.; Houston, J. D.; Mayer, T. M. & Swartzentruber, B. S.
Partner: UNT Libraries Government Documents Department

A 3-axis force balanced accelerometer using a single proof-mass

Description: This paper presents a new method for wideband force balancing a proof-mass in multiple axes simultaneously. Capacitive position sense and force feedback are accomplished using the same air-gap capacitors through time multiplexing. Proof of concept is experimentally demonstrated with a single-mass monolithic surface micromachined 3-axis accelerometer.
Date: April 1997
Creator: Lemkin, M.A.; Boser, B.E.; Auslander, D. & Smith, J.
Partner: UNT Libraries Government Documents Department

Challenges in the Packaging of MEMS

Description: The packaging of Micro-Electro-Mechanical Systems (MEMS) is a field of great importance to anyone using or manufacturing sensors, consumer products, or military applications. Currently much work has been done in the design and fabrication of MEMS devices but insufficient research and few publications have been completed on the packaging of these devices. This is despite the fact that packaging is a very large percentage of the total cost of MEMS devices. The main difference between IC packaging and MEMS packaging is that MEMS packaging is almost always application specific and greatly affected by its environment and packaging techniques such as die handling, die attach processes, and lid sealing. Many of these aspects are directly related to the materials used in the packaging processes. MEMS devices that are functional in wafer form can be rendered inoperable after packaging. MEMS dies must be handled only from the chip sides so features on the top surface are not damaged. This eliminates most current die pick-and-place fixtures. Die attach materials are key to MEMS packaging. Using hard die attach solders can create high stresses in the MEMS devices, which can affect their operation greatly. Low-stress epoxies can be high-outgassing, which can also affect device performance. Also, a low modulus die attach can allow the die to move during ultrasonic wirebonding resulting to low wirebond strength. Another source of residual stress is the lid sealing process. Most MEMS based sensors and devices require a hermetically sealed package. This can be done by parallel seam welding the package lid, but at the cost of further induced stress on the die. Another issue of MEMS packaging is the media compatibility of the packaged device. MEMS unlike ICS often interface with their environment, which could be high pressure or corrosive. The main conclusion we can draw about MEMS ...
Date: March 26, 1999
Creator: Malshe, A.P.; Singh, S.B.; Eaton, W.P.; O'Neal, C.; Brown, W.D. & Miller, W.M.
Partner: UNT Libraries Government Documents Department

Fabrication of Diffractive Optical Elements for an Integrated Compact Optical-MEMS Laser Scanner

Description: The authors describe the microfabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is {+-}4{degree} with a spot size of 0.5 mm.
Date: July 13, 2000
Partner: UNT Libraries Government Documents Department

IC-Compatible Technologies for Optical MEMS

Description: Optical Micro Electro Mechanical Systems (Optical MEMS) Technology holds the promise of one-day producing highly integrated optical systems on a common, monolithic substrate. The choice of fabrication technology used to manufacture Optical MEMS will play a pivotal role in the size, functionality and ultimately the cost of optical Microsystems. By leveraging the technology base developed for silicon integrated circuits, large batches of routers, emitters, detectors and amplifiers will soon be fabricated for literally pennies per part. In this article we review the current status of technologies used for Optical MEMS, as well as fabrication technologies of the future, emphasizing manufacturable surface micromachining approaches to producing reliable, low-cost devices for optical communications applications.
Date: April 30, 1999
Creator: Krygowski, T.W. & Sniegowski, J.J.
Partner: UNT Libraries Government Documents Department

The Influence of Coating Structure on Micromachine Stiction

Description: We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.
Date: October 3, 2000
Creator: Kushmerick, J. G.; Hankins, M. G.; De Boer, M. P.; Clews, P. J.; Carpick, R. W. & Bunker, B. C.
Partner: UNT Libraries Government Documents Department

Meso-scale machining capabilities and issues

Description: Meso-scale manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. These processes can fabricate two and three-dimensional parts having micron size features in traditional materials such as stainless steels, rare earth magnets, ceramics, and glass. Meso-scale processes that are currently available include, focused ion beam sputtering, micro-milling, micro-turning, excimer laser ablation, femto-second laser ablation, and micro electro discharge machining. These meso-scale processes employ subtractive machining technologies (i.e., material removal), unlike LIGA, which is an additive meso-scale process. Meso-scale processes have different material capabilities and machining performance specifications. Machining performance specifications of interest include minimum feature size, feature tolerance, feature location accuracy, surface finish, and material removal rate. Sandia National Laboratories is developing meso-scale electro-mechanical components, which require meso-scale parts that move relative to one another. The meso-scale parts fabricated by subtractive meso-scale manufacturing processes have unique tribology issues because of the variety of materials and the surface conditions produced by the different meso-scale manufacturing processes.
Date: May 15, 2000
Partner: UNT Libraries Government Documents Department

MEMS Packaging - Current Issues and Approaches

Description: The assembly and packaging of MEMS (Microelectromechanical Systems) devices raise a number of issues over and above those normally associated with the assembly of standard microelectronic circuits. MEMS components include a variety of sensors, microengines, optical components, and other devices. They often have exposed mechanical structures which during assembly require particulate control, space in the package, non-contact handling procedures, low-stress die attach, precision die placement, unique process schedules, hermetic sealing in controlled environments (including vacuum), and other special constraints. These constraints force changes in the techniques used to separate die on a wafer, in the types of packages which can be used in the assembly processes and materials, and in the sealing environment and process. This paper discusses a number of these issues and provides information on approaches being taken or proposed to address them.
Date: January 19, 2000
Partner: UNT Libraries Government Documents Department

Implications of intelligent, integrated microsystems for product design and development

Description: Intelligent, integrated microsystems combine some or all of the functions of sensing, processing information, actuation, and communication within a single integrated package, and preferably upon a single silicon chip. As the elements of these highly integrated solutions interact strongly with each other, the microsystem can be neither designed nor fabricated piecemeal, in contrast to the more familiar assembled products. Driven by technological imperatives, microsystems will best be developed by multi-disciplinary teams, most likely within the flatter, less hierarchical organizations. Standardization of design and process tools around a single, dominant technology will expedite economically viable operation under a common production infrastructure. The production base for intelligent, integrated microsystems has elements in common with the mathematical theory of chaos. Similar to chaos theory, the development of microsystems technology will be strongly dependent on, and optimized to, the initial product requirements that will drive standardization--thereby further rewarding early entrants to integrated microsystem technology.
Date: April 19, 2000
Partner: UNT Libraries Government Documents Department

Testing of Critical Features of Polysilicon MEMS

Description: The behavior of MEMS devices is limited by the strength of critical features such as thin ligaments, oxide cuts joining layers, pin joints and hinges. Devices fabricated at Sandia's Microelectronic Development Laboratory have been successfully tested to investigate these features. A series of measurements were performed on samples with gage lengths of 15 to 1000 microns, using conventional and tungsten coated samples as well as samples that include the critical features of standard components in the test section. Specimens have a freely moving pin joint on one end that anchors the sample to the silicon die to allow rotation to reduce effects of bending. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. Load is calculated by resolving the measured lateral and normal forces into the applied tensile force and frictional losses. The specimen cross section and gage length dimensions were verified by measuring against a standard in the SEM. Multiple tests can be programmed at one time and performed without operator assistance allowing the collection of significant populations of data.
Date: December 2, 1999
Partner: UNT Libraries Government Documents Department

The Impact of Emerging MEMS-Based Microsystems on US Defense Applications

Description: This paper examines the impact of inserting Micro-Electro-Mechanical Systems (MEMS) into US defense applications. As specific examples, the impacts of micro Inertial Measurement Units (IMUs), radio frequency MEMS (RF MEMS), and Micro-Opto-Electro-Mechanical Systems (MOEMS) to provide integrated intelligence, communication, and control to the defense infrastructure with increased affordability, functionality, and performance are highlighted.
Date: January 20, 2000
Partner: UNT Libraries Government Documents Department

CRADA Final Report-Dual Manifold System for Arraying Biomolecules

Description: The objective of this CRADA is to establish a new approach to fluid transfer and array construction. This new approach will involve a high-speed, multiplexed fluid distribution valve and ink jet valves. It will enable the parallel handling of multiple reagents for a system that will have multiple applications in addition to the high-speed construction of microarrays. The primary tasks involve proof of principle experiments aimed at establishing key components of the technology and evaluating various optional configurations. The basic platform for evaluating the technology will be set-up by the Contractor at Oak Ridge National Laboratory (ORNL) and will employ custom valving prepared by Rheodyne. The test platform will consist of a motion controller, 3-axes of motion, software, and pneumatic control; and will be used to evaluate the hybrid valve.
Date: May 8, 2001
Creator: Doktycz, M.J.
Partner: UNT Libraries Government Documents Department

Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS)

Description: A review is made of the infrastructure, technology and capabilities of Sandia National Laboratories for the development of micromechanical systems. By incorporating advanced fabrication processes, such as chemical mechanical polishing, and several mechanical polysilicon levels, the range of micromechanical systems that can be fabricated in these technologies is virtually limitless. Representative applications include a micro-engine driven mirror, and a micromachined lock. Using a novel integrated MEMS/CMOS technology, a six degree-of-freedom accelerometer/gyroscope system has been designed by researchers at U.C. Berkeley and fabricated on the same silicon chip as the CMOS control circuits to produce an integrated micro-navigational unit.
Date: July 9, 1999
Creator: Allen, J.J.; Jakubczak, J.F.; Krygowski, T.W.; Miller, S.L.; Montague, S.; Rodgers, M.S. et al.
Partner: UNT Libraries Government Documents Department